SEC Info - CNA Financial Corp. - ‘10-K’ for 12/31/22

SEC Info℠

Home

My Interests

Help

Please Sign In

CNA Financial Corp. – ‘10-K’ for 12/31/22 – ‘EX-101.DEF’

On: Tuesday, 2/7/23, at 4:39pm ET · For: 12/31/22 · Accession #: 21175-23-6 · File #: 1-05823

Previous ‘10-K’: ‘10-K’ on 2/8/22 for 12/31/21 · Next & Latest: ‘10-K’ on 2/6/24 for 12/31/23 · 19 References:

  As Of               Filer                 Filing    For·On·As Docs:Size

 2/07/23  CNA Financial Corp.               10-K       12/31/22  163:35M

Annual Report — Form 10-K

Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   7.85M 
 2: EX-21.1     Subsidiaries List                                   HTML     53K 
 3: EX-23.1     Consent of Expert or Counsel                        HTML     50K 
 4: EX-31.1     Certification -- §302 - SOA'02                      HTML     55K 
 5: EX-31.2     Certification -- §302 - SOA'02                      HTML     55K 
 6: EX-32.1     Certification -- §906 - SOA'02                      HTML     52K 
 7: EX-32.2     Certification -- §906 - SOA'02                      HTML     52K 
13: R1          Cover Page                                          HTML    118K 
14: R2          Audit Information                                   HTML     55K 
15: R3          Consolidated Statements of Operations               HTML    134K 
16: R4          Consolidated Statements of Comprehensive (Loss)     HTML     83K 
                Income                                                           
17: R5          Consolidated Balance Sheets                         HTML    158K 
18: R6          Consolidated Balance Sheets - (Parenthetical)       HTML     82K 
19: R7          Consolidated Statements of Cash Flows               HTML    154K 
20: R8          Consolidated Statements of Stockholders' Equity     HTML     89K 
21: R9          Consolidated Statements of Stockholders' Equity -   HTML     52K 
                (Parenthetical)                                                  
22: R10         Summary of Significant Accounting Policies          HTML    113K 
23: R11         Investments                                         HTML    350K 
24: R12         Fair Value                                          HTML    236K 
25: R13         Income Taxes                                        HTML     98K 
26: R14         Claim and Claim Adjustment Expense Reserves and     HTML   1.44M 
                Future Policy Benefit Reserves                                   
27: R15         Legal Proceedings, Contingencies and Guarantees     HTML     53K 
28: R16         Reinsurance                                         HTML    138K 
29: R17         Debt                                                HTML     77K 
30: R18         Benefit Plans                                       HTML    222K 
31: R19         Stock-Based Compensation                            HTML     65K 
32: R20         Other Intangible Assets                             HTML     73K 
33: R21         Leases                                              HTML     66K 
34: R22         Stockholders' Equity and Statutory Accounting       HTML     68K 
                Practices                                                        
35: R23         Accumulated Other Comprehensive Income (Loss) by    HTML     90K 
                Component                                                        
36: R24         Business Segments                                   HTML    351K 
37: R25         Related Party Transactions                          HTML     54K 
38: R26         Non-Insurance Revenues from Contracts with          HTML     57K 
                Customers                                                        
39: R27         Schedule I. Summary of Investments - Other Than     HTML     53K 
                Investments in Related Parties                                   
40: R28         Schedule II. Condensed Financial Information of     HTML    133K 
                Registrant (Parent Company)                                      
41: R29         Schedule III. Supplementary Insurance Information   HTML     52K 
42: R30         Schedule IV. Reinsurance                            HTML     53K 
43: R31         Schedule V. Valuation and Qualifying Accounts       HTML     91K 
44: R32         Schedule VI. Supplemental Information Concerning    HTML     71K 
                Property and Casualty Insurance Operations                       
45: R33         Summary of Significant Accounting Policies          HTML    165K 
                (Policies)                                                       
46: R34         Investments (Tables)                                HTML    349K 
47: R35         Fair Value (Tables)                                 HTML    232K 
48: R36         Income Taxes (Tables)                               HTML     96K 
49: R37         Claim and Claim Adjustment Expense Reserves and     HTML   1.44M 
                Future Policy Benefit Reserves (Tables)                          
50: R38         Reinsurance (Tables)                                HTML    134K 
51: R39         Debt (Tables)                                       HTML     73K 
52: R40         Benefit Plans (Tables)                              HTML    219K 
53: R41         Stock-Based Compensation (Tables)                   HTML     59K 
54: R42         Other Intangible Assets (Tables)                    HTML     72K 
55: R43         Leases (Tables)                                     HTML     69K 
56: R44         Stockholders' Equity and Statutory Accounting       HTML     60K 
                Practices (Tables)                                               
57: R45         Accumulated Other Comprehensive Income (Loss) by    HTML     91K 
                Component (Tables)                                               
58: R46         Business Segments (Tables)                          HTML    345K 
59: R47         Summary of Significant Accounting Policies          HTML    147K 
                (Narrative) (Details)                                            
60: R48         Investments (Net investment income) (Details)       HTML     79K 
61: R49         Investments (Narrative) (Details)                   HTML    133K 
62: R50         Investments (Net realized investment gains          HTML     67K 
                (Losses)) (Details)                                              
63: R51         Investments (Components of other-than-temporary     HTML     57K 
                impairment losses recognized in earnings)                        
                (Details)                                                        
64: R52         Investments (Summary of fixed maturity and equity   HTML    109K 
                securities) (Details)                                            
65: R53         Investments (Securities in a gross unrealized loss  HTML    100K 
                position) (Details)                                              
66: R54         Investments (Securities in a gross unrealized loss  HTML     71K 
                position by ratings) (Details)                                   
67: R55         Investments (Allowance on available-for-sale        HTML     79K 
                securities with credit impairments and PCD assets                
                activity) (Details)                                              
68: R56         Investments (Contractual maturity) (Details)        HTML     77K 
69: R57         Investments (Credit quality indicator) (Details)    HTML    103K 
70: R58         Fair Value (Assets and liabilities measured at      HTML    101K 
                fair value on a recurring basis) (Details)                       
71: R59         Fair Value (Table of reconciliation for assets and  HTML    118K 
                liabilities measured at fair value on a recurring                
                basis using significant unobservable inputs)                     
                (Details)                                                        
72: R60         Fair Value (Narrative) (Details)                    HTML     51K 
73: R61         Fair Value (Quantitative information about          HTML     65K 
                significant unobservable inputs in the fair value                
                measurement of level 3 assets) (Details)                         
74: R62         Fair Value (Carrying amount and estimated fair      HTML     74K 
                value of financial instrument assets and                         
                liabilities which are not measured at fair value)                
                (Details)                                                        
75: R63         Income Taxes (Narrative) (Details)                  HTML     82K 
76: R64         Income Taxes (Reconciliation between the Company's  HTML     66K 
                federal income tax (Expense) Benefit at Statutory                
                Rates and the Recorded Income Tax (Expense)                      
                Benefit) (Details)                                               
77: R65         Income Taxes (Current and deferred components of    HTML     61K 
                the Company's income tax (Expense) Benefit)                      
                (Details)                                                        
78: R66         Income Taxes (Significant components of the         HTML     86K 
                Company's deferred tax assets and liabilities)                   
                (Details)                                                        
79: R67         Claim and Claim Adjustment Expense Reserves and     HTML     73K 
                Future Policy Benefit Reserves (Reconciliation of                
                Liability for Unpaid Claim and Claim Adjustment                  
                Expense) (Details)                                               
80: R68         Claim and Claim Adjustment Expense Reserves and     HTML     82K 
                Future Policy Benefit Reserves (Reconciliation of                
                Claim and Claim Adjustment Expense Reserves)                     
                (Details)                                                        
81: R69         Claim and Claim Adjustment Expense Reserves and     HTML     88K 
                Future Policy Benefit Reserves (Gross and Net                    
                Carried Claim and Claim Adjustment Expense                       
                Reserves) (Details)                                              
82: R70         Claim and Claim Adjustment Expense Reserves and     HTML     61K 
                Future Policy Benefit Reserves (Net Prior Year                   
                Development) (Details)                                           
83: R71         Claim and Claim Adjustment Expense Reserves and     HTML    114K 
                Future Policy Benefit Reserves (Narrative)                       
                (Details)                                                        
84: R72         Claim and Claim Adjustment Expense Reserves and     HTML     64K 
                Future Policy Benefit Reserves (Specialty - Net                  
                Prior Year Claim and Allocated Claim Adjustment                  
                Expense Reserve Development) (Details)                           
85: R73         Claim and Claim Adjustment Expense Reserves and     HTML     68K 
                Future Policy Benefit Reserves (Specialty - Line                 
                of Business Composition) (Details)                               
86: R74         Claim and Claim Adjustment Expense Reserves and     HTML    106K 
                Future Policy Benefit Reserves (Specialty -                      
                Medical Professional Liability - Cumulative Net                  
                Incurred Claims and Allocated Claim Adjustment                   
                Expenses) (Details)                                              
87: R75         Claim and Claim Adjustment Expense Reserves and     HTML    105K 
                Future Policy Benefit Reserves (Specialty -                      
                Medical Professional Liability - Net Cumulative                  
                Paid Claim and Claim Adjustment Expenses)                        
                (Details)                                                        
88: R76         Claim and Claim Adjustment Expense Reserves and     HTML    103K 
                Future Policy Benefit Reserves (Specialty -                      
                Medical Professional Liability - Net Strengthening               
                or Releasing of Prior Accident Year Reserves)                    
                (Details)                                                        
89: R77         Claim and Claim Adjustment Expense Reserves and     HTML    106K 
                Future Policy Benefit Reserves (Specialty - Other                
                Professional Liability and Management Liability -                
                Net Incurred Claims and Allocated Claim Adjustment               
                Expenses) (Details)                                              
90: R78         Claim and Claim Adjustment Expense Reserves and     HTML    105K 
                Future Policy Benefit Reserves (Specialty - Other                
                Professional Liability and Management Liability -                
                Net Cumulative Paid Claim and Claim Adjustment                   
                Expenses) (Details)                                              
91: R79         Claim and Claim Adjustment Expense Reserves and     HTML    103K 
                Future Policy Benefit Reserves (Specialty - Other                
                Professional Liability and Management Liability -                
                Net Strengthening or Releasing of Prior Accident                 
                Year Reserves) (Details)                                         
92: R80         Claim and Claim Adjustment Expense Reserves and     HTML    105K 
                Future Policy Benefit Reserves (Specialty - Surety               
                - Net Incurred Claims and Allocated Claim                        
                Adjustment Expenses) (Details)                                   
93: R81         Claim and Claim Adjustment Expense Reserves and     HTML    105K 
                Future Policy Benefit Reserves (Specialty - Surety               
                - Net Cumulative Paid Claim and Claim Adjustment                 
                Expenses) (Details)                                              
94: R82         Claim and Claim Adjustment Expense Reserves and     HTML    102K 
                Future Policy Benefit Reserves (Specialty - Surety               
                - Net Strengthening or Releasing of Prior Accident               
                Year Reserves) (Details)                                         
95: R83         Claim and Claim Adjustment Expense Reserves and     HTML     62K 
                Future Policy Benefit Reserves (Commercial - Net                 
                Prior Year Claim and Allocated Claim Adjustment                  
                Expense Reserve Development) (Details)                           
96: R84         Claim and Claim Adjustment Expense Reserves and     HTML     66K 
                Future Policy Benefit Reserves (Commercial -                     
                Commercial Auto - Short Duration Contracts)                      
                (Details)                                                        
97: R85         Claim and Claim Adjustment Expense Reserves and     HTML    106K 
                Future Policy Benefit Reserves (Commercial -                     
                Commercial Auto - Net Incurred Claims and                        
                Allocated Claim Adjustment Expenses) (Details)                   
98: R86         Claim and Claim Adjustment Expense Reserves and     HTML    105K 
                Future Policy Benefit Reserves (Commercial -                     
                Commercial Auto - Net Cumulative Paid Claim and                  
                Claim Adjustment Expenses) (Details)                             
99: R87         Claim and Claim Adjustment Expense Reserves and     HTML    104K 
                Future Policy Benefit Reserves (Commercial -                     
                Commercial Auto - Net Strengthening or Releasing                 
                of Prior Accident Year Reserves) (Details)                       
100: R88         Claim and Claim Adjustment Expense Reserves and     HTML    106K  
                Future Policy Benefit Reserves (Commercial -                     
                General Liability - Net Incurred Claims and                      
                Allocated Claim Adjustment Expenses) (Details)                   
101: R89         Claim and Claim Adjustment Expense Reserves and     HTML    105K  
                Future Policy Benefit Reserves (Commercial -                     
                General Liability - Net Cumulative Paid Claim and                
                Claim Adjustment Expenses) (Details)                             
102: R90         Claim and Claim Adjustment Expense Reserves and     HTML    104K  
                Future Policy Benefit Reserves (Commercial -                     
                General Liability - Net Strengthening or Releasing               
                of Prior Accident Year Reserves) (Details)                       
103: R91         Claim and Claim Adjustment Expense Reserves and     HTML    106K  
                Future Policy Benefit Reserves (Commercial -                     
                Workers' Compensation - Net Incurred Claims and                  
                Allocated Claim Adjustment Expenses) (Details)                   
104: R92         Claim and Claim Adjustment Expense Reserves and     HTML    108K  
                Future Policy Benefit Reserves (Commercial -                     
                Workers' Compensation - Net Cumulative Paid Claim                
                and Claim Adjustment Expenses) (Details)                         
105: R93         Claim and Claim Adjustment Expense Reserves and     HTML    106K  
                Future Policy Benefit Reserves (Commercial -                     
                Workers' Compensation - Net Strengthening or                     
                Releasing of Prior Accident Year Reserves)                       
                (Details)                                                        
106: R94         Claim and Claim Adjustment Expense Reserves and     HTML     60K  
                Future Policy Benefit Reserves (International -                  
                Net prior year claim and allocated claim                         
                adjustment expense reserve development) (Details)                
107: R95         Claim and Claim Adjustment Expense Reserves and     HTML     61K  
                Future Policy Benefit Reserves (International -                  
                Short Duration Contracts) (Details)                              
108: R96         Claim and Claim Adjustment Expense Reserves and     HTML    106K  
                Future Policy Benefit Reserves (International -                  
                Excluding Hardy - Net Incurred Claims and                        
                Allocated Claim Adjustment Expenses) (Details)                   
109: R97         Claim and Claim Adjustment Expense Reserves and     HTML    105K  
                Future Policy Benefit Reserves (International -                  
                Excluding Hardy - Net Cumulative Paid Claim and                  
                Claim Adjustment Expenses) (Details)                             
110: R98         Claim and Claim Adjustment Expense Reserves and     HTML     91K  
                Future Policy Benefit Reserves (International -                  
                Excluding Hardy - Net Strengthening or Releasing                 
                of Prior Accident Year Reserves) (Details)                       
111: R99         Claim and Claim Adjustment Expense Reserves and     HTML    143K  
                Future Policy Benefit Reserves (International -                  
                Hardy - Net Incurred Claims and Allocated Claim                  
                Adjustment Expenses) (Details)                                   
112: R100        Claim and Claim Adjustment Expense Reserves and     HTML    104K  
                Future Policy Benefit Reserves (International -                  
                Hardy - Net Cumulative Paid Claim and Claim                      
                Adjustment Expenses) (Details)                                   
113: R101        Claim and Claim Adjustment Expense Reserves and     HTML     91K  
                Future Policy Benefit Reserves (International -                  
                Hardy - Net Strengthening or Releasing of Prior                  
                Accident Year Reserves) (Details)                                
114: R102        Claim and Claim Adjustment Expense Reserves and     HTML    110K  
                Future Policy Benefit Reserves (Historical Claims                
                Duration) (Details)                                              
115: R103        Claim and Claim Adjustment Expense Reserves and     HTML     61K  
                Future Policy Benefit Reserves (Impact of Loss                   
                Portfolio Transfer on the Consolidated Statement                 
                of Operations) (Details)                                         
116: R104        Claim and Claim Adjustment Expense Reserves and     HTML     56K  
                Future Policy Benefit Reserves (Life & Group                     
                Policyholder Reserves) (Details)                                 
117: R105        Legal Proceedings, Contingencies and Guarantees     HTML     54K  
                (Narrative) (Details)                                            
118: R106        Reinsurance (Components of Reinsurance              HTML     64K  
                Receivables) (Details)                                           
119: R107        Reinsurance (Voluntary Reinsurance) (Details)       HTML     57K  
120: R108        Reinsurance (Narrative) (Details)                   HTML     69K  
121: R109        Reinsurance (Components of Earned Premiums)         HTML     75K  
                (Details)                                                        
122: R110        Reinsurance (Components of Written Premiums)        HTML     71K  
                (Details)                                                        
123: R111        Debt (Schedule of debt instruments) (Details)       HTML     81K  
124: R112        Debt (Narrative) (Details)                          HTML     73K  
125: R113        Debt (Maturity of debt) (Details)                   HTML     73K  
126: R114        Benefit Plans (Funded Status) (Details)             HTML    126K  
127: R115        Benefit Plans (Narrative) (Details)                 HTML     94K  
128: R116        Benefit Plans (Components of Net Periodic Cost      HTML     67K  
                (Benefit)) (Details)                                             
129: R117        Benefit Plans (Schedule of Non-Service Cost         HTML     59K  
                (Benefit) Presented in the Consolidated Statement                
                of Operations) (Details)                                         
130: R118        Benefit Plans (Schedule of Amounts Recognized in    HTML     65K  
                Other Comprehensive Income) (Details)                            
131: R119        Benefit Plans (Actuarial Assumptions for Benefit    HTML     58K  
                Obligations) (Details)                                           
132: R120        Benefit Plans (Actuarial Assumptions for Net Cost   HTML     61K  
                or Benefit) (Details)                                            
133: R121        Benefit Plans (Fair Value of Plan Assets Measured   HTML    119K  
                on a Recurring Basis) (Details)                                  
134: R122        Benefit Plans (Estimated Future Minimum Benefit     HTML     68K  
                Payments to Participants) (Details)                              
135: R123        Stock-Based Compensation (Narrative) (Details)      HTML     83K  
136: R124        Stock-Based Compensation (Restricted shares,        HTML     79K  
                performance-based restricted share units and                     
                performance share unit activity) (Details)                       
137: R125        Other Intangible Assets (Summary of Other           HTML     73K  
                Intangible Assets) (Details)                                     
138: R126        Other Intangible Assets (Narrative) (Details)       HTML     67K  
139: R127        Leases (Narrative) (Detail)                         HTML     61K  
140: R128        Leases (Assets and Liabilities) (Details)           HTML     53K  
141: R129        Leases (Maturities) (Details)                       HTML     69K  
142: R130        Leases (Lease Term and Discount Rate) (Details)     HTML     54K  
143: R131        Stockholders' Equity and Statutory Accounting       HTML     59K  
                Practices (Narrative) (Details)                                  
144: R132        Stockholders' Equity and Statutory Accounting       HTML     56K  
                Practices (Combined statutory capital and surplus                
                and net income (Loss)) (Details)                                 
145: R133        Accumulated Other Comprehensive Income (Loss) by    HTML     90K  
                Component (Schedule of Accumulated Other                         
                Comprehensive Income (Loss) by Component)                        
                (Details)                                                        
146: R134        Business Segments (Narrative) (Details)             HTML     59K  
147: R135        Business Segments (Income Statement Information)    HTML    154K  
                (Details)                                                        
148: R136        Business Segments (Balance Sheet Information)       HTML    108K  
                (Details)                                                        
149: R137        Business Segments (Revenues by Line of Business)    HTML     90K  
                (Details)                                                        
150: R138        Related Party Transactions Narrative (Details)      HTML     71K  
151: R139        Non-Insurance Revenues from Contracts with          HTML     65K  
                Customers (Narrative) (Details)                                  
152: R140        Non-Insurance Revenues from Contracts with          HTML     64K  
                Customers (Performance obligation) (Details)                     
153: R141        Schedule II. Condensed Financial Information of     HTML    104K  
                Registrant (Parent Company) (Schedule of Condensed               
                Financial Information of Registrant, Statements of               
                Operations and Comprehensive Income (Loss))                      
                (Details)                                                        
154: R142        Schedule II. Condensed Financial Information of     HTML    132K  
                Registrant (Parent Company) (Schedule of Condensed               
                Financial Information of Registrant, Balance                     
                Sheets) (Details)                                                
155: R143        Schedule II. Condensed Financial Information of     HTML    115K  
                Registrant (Parent Company) (Schedule of Condensed               
                Financial Information of Registrant, Statements of               
                Cash Flows) (Details)                                            
156: R144        Schedule II. Condensed Financial Information of     HTML     54K  
                Registrant (Parent Company) (Narrative) (Details)                
157: R145        Schedule V. Valuation and Qualifying Accounts       HTML     69K  
                (Schedule of valuation and qualifying accounts)                  
                (Details)                                                        
158: R146        Schedule VI. Supplemental Information Concerning    HTML     85K  
                Property and Casualty Insurance Operations                       
                (Details)                                                        
161: XML         IDEA XML File -- Filing Summary                      XML    350K  
159: XML         XBRL Instance -- cna-20221231_htm                    XML  12.97M  
160: EXCEL       IDEA Workbook of Financial Reports                  XLSX    417K  
 9: EX-101.CAL  XBRL Calculations -- cna-20221231_cal                XML    482K 
10: EX-101.DEF  XBRL Definitions -- cna-20221231_def                 XML   2.31M 
11: EX-101.LAB  XBRL Labels -- cna-20221231_lab                      XML   3.34M 
12: EX-101.PRE  XBRL Presentations -- cna-20221231_pre               XML   2.88M 
 8: EX-101.SCH  XBRL Schema -- cna-20221231                          XSD    415K 
162: JSON        XBRL Instance as JSON Data -- MetaLinks              861±  1.51M  
163: ZIP         XBRL Zipped Folder -- 0000021175-23-000006-xbrl      Zip   1.35M

‘EX-101.DEF’ — XBRL Definitions — cna-20221231_def

This Exhibit is an XBRL XML File.

<?xml version="1.0" encoding="windows-1252"?>

<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">

<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>

<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>

<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>

<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>

<link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>

<link:roleRef roleURI="http://www.cna.com/role/CoverPage" xlink:type="simple" xlink:href="cna-20221231.xsd#CoverPage"/>

<link:definitionLink xlink:role="http://www.cna.com/role/CoverPage" xlink:type="extended" id="i985851197fa545ac8ff6941089d30056_CoverPage">

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityInformationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_512e80f4-01ba-4037-9892-5f0af8c10faa" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentType"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentType_512e80f4-01ba-4037-9892-5f0af8c10faa" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport_3324b719-5eb2-4f08-9972-a5ab6ce24195" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentAnnualReport"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentAnnualReport_3324b719-5eb2-4f08-9972-a5ab6ce24195" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_776353e4-e4b0-41a9-b288-4284b652debe" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentPeriodEndDate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentPeriodEndDate_776353e4-e4b0-41a9-b288-4284b652debe" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_1df3bae8-dcf4-4486-9897-6a36fc55cc5f" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CurrentFiscalYearEndDate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_CurrentFiscalYearEndDate_1df3bae8-dcf4-4486-9897-6a36fc55cc5f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_8f2015ae-11d9-46c5-b96e-081bb8321370" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentTransitionReport"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentTransitionReport_8f2015ae-11d9-46c5-b96e-081bb8321370" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_82b9cc6a-fc1a-4338-8520-af9b86e071c6" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFileNumber"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityFileNumber_82b9cc6a-fc1a-4338-8520-af9b86e071c6" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_0af50005-467b-4491-9ebd-8ea66d2e82d0" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityRegistrantName"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityRegistrantName_0af50005-467b-4491-9ebd-8ea66d2e82d0" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_3ed55df7-5989-4be8-acb1-c2f1fa8a4071" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityIncorporationStateCountryCode"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityIncorporationStateCountryCode_3ed55df7-5989-4be8-acb1-c2f1fa8a4071" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_6b2697cb-77ef-4f97-816e-19edcd724e28" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityTaxIdentificationNumber"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityTaxIdentificationNumber_6b2697cb-77ef-4f97-816e-19edcd724e28" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_dc337910-3af6-4467-accc-fda2c37bfb7e" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressAddressLine1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityAddressAddressLine1_dc337910-3af6-4467-accc-fda2c37bfb7e" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_c44917ef-c2bd-4057-bc90-abd8cc93eab3" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressPostalZipCode"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityAddressPostalZipCode_c44917ef-c2bd-4057-bc90-abd8cc93eab3" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_33a19ef8-8ebe-4c4e-bd5e-28e3317c7006" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressCityOrTown"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityAddressCityOrTown_33a19ef8-8ebe-4c4e-bd5e-28e3317c7006" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_e7508079-06cc-40b0-80b7-88604007f595" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressStateOrProvince"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityAddressStateOrProvince_e7508079-06cc-40b0-80b7-88604007f595" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_d6bebb79-7d37-467f-8e56-0e2f68fefe1a" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CityAreaCode"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_CityAreaCode_d6bebb79-7d37-467f-8e56-0e2f68fefe1a" xlink:type="arc" order="13"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_6ef26684-4cab-4eed-844a-89a9e7ef8ac2" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_LocalPhoneNumber"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_LocalPhoneNumber_6ef26684-4cab-4eed-844a-89a9e7ef8ac2" xlink:type="arc" order="14"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_771f1f5f-fd0a-4d08-984f-7872ca0f9b84" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_Security12bTitle"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_Security12bTitle_771f1f5f-fd0a-4d08-984f-7872ca0f9b84" xlink:type="arc" order="15"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_a27feae3-8151-489e-b9a9-550911f7c5ae" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_TradingSymbol"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_TradingSymbol_a27feae3-8151-489e-b9a9-550911f7c5ae" xlink:type="arc" order="16"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_0655dfe7-5645-49d5-a1f8-72429554d981" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_SecurityExchangeName"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_SecurityExchangeName_0655dfe7-5645-49d5-a1f8-72429554d981" xlink:type="arc" order="17"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_0077ea10-494b-47cf-b5ea-193aac9575a1" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityWellKnownSeasonedIssuer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_0077ea10-494b-47cf-b5ea-193aac9575a1" xlink:type="arc" order="18"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityVoluntaryFilers_1ea68e60-27c1-499a-8dda-1e8e2660f418" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityVoluntaryFilers"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityVoluntaryFilers_1ea68e60-27c1-499a-8dda-1e8e2660f418" xlink:type="arc" order="19"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_abec298e-be7c-4fe5-93ee-51b04d400ab6" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCurrentReportingStatus"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityCurrentReportingStatus_abec298e-be7c-4fe5-93ee-51b04d400ab6" xlink:type="arc" order="20"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_d034be50-c832-4092-bae0-8c3e9dd88428" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityInteractiveDataCurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityInteractiveDataCurrent_d034be50-c832-4092-bae0-8c3e9dd88428" xlink:type="arc" order="21"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_382541fc-7aac-493b-aecf-53c7e66d33be" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFilerCategory"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityFilerCategory_382541fc-7aac-493b-aecf-53c7e66d33be" xlink:type="arc" order="22"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_12d74794-e7b5-4b98-8b73-42ab2ea5bcd0" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntitySmallBusiness"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntitySmallBusiness_12d74794-e7b5-4b98-8b73-42ab2ea5bcd0" xlink:type="arc" order="23"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_9d3d8d24-8d7a-4eab-9c2f-6f3d4428fb6e" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityEmergingGrowthCompany"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityEmergingGrowthCompany_9d3d8d24-8d7a-4eab-9c2f-6f3d4428fb6e" xlink:type="arc" order="24"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_IcfrAuditorAttestationFlag_dd75fc5f-9891-4dda-8bba-7bea4abec93d" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_IcfrAuditorAttestationFlag"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_IcfrAuditorAttestationFlag_dd75fc5f-9891-4dda-8bba-7bea4abec93d" xlink:type="arc" order="25"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_bb5d426d-c30e-4200-8591-910c75ccda58" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityShellCompany"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityShellCompany_bb5d426d-c30e-4200-8591-910c75ccda58" xlink:type="arc" order="26"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_dc63e795-6c94-43e9-ad25-f069b0b9f80d" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCommonStockSharesOutstanding"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_dc63e795-6c94-43e9-ad25-f069b0b9f80d" xlink:type="arc" order="27"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat_13407a8b-f6b4-4b9a-b94d-9f765e93dea0" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityPublicFloat"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityPublicFloat_13407a8b-f6b4-4b9a-b94d-9f765e93dea0" xlink:type="arc" order="28"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock_5b34ce88-607a-42f1-91e7-7df202d3644e" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentsIncorporatedByReferenceTextBlock_5b34ce88-607a-42f1-91e7-7df202d3644e" xlink:type="arc" order="29"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_f641b9e3-b77c-4654-8469-c6e72ae5ae7d" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCentralIndexKey"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntityCentralIndexKey_f641b9e3-b77c-4654-8469-c6e72ae5ae7d" xlink:type="arc" order="30"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_ae84e1b1-f475-4918-8dd2-349efcbe17c5" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalYearFocus"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentFiscalYearFocus_ae84e1b1-f475-4918-8dd2-349efcbe17c5" xlink:type="arc" order="31"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_a67a6307-d680-42db-a957-eaca0f5e22a0" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalPeriodFocus"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_DocumentFiscalPeriodFocus_a67a6307-d680-42db-a957-eaca0f5e22a0" xlink:type="arc" order="32"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_4d9b9ebc-b56f-4380-83b8-4c68d9615b49" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AmendmentFlag"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_AmendmentFlag_4d9b9ebc-b56f-4380-83b8-4c68d9615b49" xlink:type="arc" order="33"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_dd8ac246-038f-4a24-bc64-18399d37e06b" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntitiesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_62aea387-e9ab-4a42-843d-239774a43fce" xlink:to="loc_dei_EntitiesTable_dd8ac246-038f-4a24-bc64-18399d37e06b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityListingsExchangeAxis_f90a724a-6e16-4d34-8e40-f6ea0a0e095c" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityListingsExchangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_dd8ac246-038f-4a24-bc64-18399d37e06b" xlink:to="loc_dei_EntityListingsExchangeAxis_f90a724a-6e16-4d34-8e40-f6ea0a0e095c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_f90a724a-6e16-4d34-8e40-f6ea0a0e095c_default" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_ExchangeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_EntityListingsExchangeAxis_f90a724a-6e16-4d34-8e40-f6ea0a0e095c" xlink:to="loc_dei_ExchangeDomain_f90a724a-6e16-4d34-8e40-f6ea0a0e095c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_ExchangeDomain_1eaeb9ae-43f6-44ad-af60-49e29a899c80" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_ExchangeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_EntityListingsExchangeAxis_f90a724a-6e16-4d34-8e40-f6ea0a0e095c" xlink:to="loc_dei_ExchangeDomain_1eaeb9ae-43f6-44ad-af60-49e29a899c80" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_exch_XNYS_399aa622-630a-4e9a-b842-3b59989f7dbe" xlink:href="https://xbrl.sec.gov/exch/2022/exch-2022.xsd#exch_XNYS"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_1eaeb9ae-43f6-44ad-af60-49e29a899c80" xlink:to="loc_exch_XNYS_399aa622-630a-4e9a-b842-3b59989f7dbe" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_exch_XCHI_5c3418a1-6eed-4d21-9e0a-f955ab306cba" xlink:href="https://xbrl.sec.gov/exch/2022/exch-2022.xsd#exch_XCHI"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_ExchangeDomain_1eaeb9ae-43f6-44ad-af60-49e29a899c80" xlink:to="loc_exch_XCHI_5c3418a1-6eed-4d21-9e0a-f955ab306cba" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ConsolidatedStatementsofComprehensiveLossIncome" xlink:type="simple" xlink:href="cna-20221231.xsd#ConsolidatedStatementsofComprehensiveLossIncome"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ConsolidatedStatementsofComprehensiveLossIncome" xlink:type="extended" id="i4a635af7f0024ffdaf22e1334e7802e2_ConsolidatedStatementsofComprehensiveLossIncome">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_a6dcd800-2846-48d8-8770-84f40f09474d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_dc3d2a95-3a80-4247-b10e-de8aaf4d6167" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6dcd800-2846-48d8-8770-84f40f09474d" xlink:to="loc_us-gaap_NetIncomeLoss_dc3d2a95-3a80-4247-b10e-de8aaf4d6167" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6dcd800-2846-48d8-8770-84f40f09474d" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax_7b89607e-8e60-4e92-b613-2b3082cf21b8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeReclassificationAdjustmentsNetOfTax_7b89607e-8e60-4e92-b613-2b3082cf21b8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_8e405cae-4a67-4031-ad64-a8f9e159dc2d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_8e405cae-4a67-4031-ad64-a8f9e159dc2d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_a4612503-9d84-4a7e-b3b5-d39a24f06209" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_a4612503-9d84-4a7e-b3b5-d39a24f06209" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_fdba65ae-603d-4330-a71c-126a00e99754" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecreaseAbstract_4e70a9d1-db8d-437a-9f94-42c6f0775e02" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_fdba65ae-603d-4330-a71c-126a00e99754" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_cc6a4d4d-4040-4c97-968a-0125c15872af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_a6dcd800-2846-48d8-8770-84f40f09474d" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_cc6a4d4d-4040-4c97-968a-0125c15872af" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_d1b15924-37ce-429a-b00a-d8c5ac3b7a85" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_a6dcd800-2846-48d8-8770-84f40f09474d" xlink:to="loc_us-gaap_StatementTable_d1b15924-37ce-429a-b00a-d8c5ac3b7a85" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_5b9c72e6-4906-4bbd-8011-9b5f46d3351d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_d1b15924-37ce-429a-b00a-d8c5ac3b7a85" xlink:to="loc_us-gaap_FinancialInstrumentAxis_5b9c72e6-4906-4bbd-8011-9b5f46d3351d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b9c72e6-4906-4bbd-8011-9b5f46d3351d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5b9c72e6-4906-4bbd-8011-9b5f46d3351d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5b9c72e6-4906-4bbd-8011-9b5f46d3351d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b69f230f-1eb0-46a8-9f32-87f8968def9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5b9c72e6-4906-4bbd-8011-9b5f46d3351d" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b69f230f-1eb0-46a8-9f32-87f8968def9f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_9864f5ec-b482-4f93-aded-77bcc642351a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b69f230f-1eb0-46a8-9f32-87f8968def9f" xlink:to="loc_us-gaap_InvestmentsMember_9864f5ec-b482-4f93-aded-77bcc642351a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInvestmentsMember_c4707f73-74bd-4e68-a948-64d91ecbd569" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherInvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b69f230f-1eb0-46a8-9f32-87f8968def9f" xlink:to="loc_us-gaap_OtherInvestmentsMember_c4707f73-74bd-4e68-a948-64d91ecbd569" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="cna-20221231.xsd#ConsolidatedStatementsofStockholdersEquity"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended" id="i758878ba11cc419c8db97d74a8faf5fb_ConsolidatedStatementsofStockholdersEquity">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_40681089-f40f-4d00-9292-22092830bbe7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_40681089-f40f-4d00-9292-22092830bbe7" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6270541f-9aae-44cf-a340-87470d5bba62" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_StockholdersEquity_6270541f-9aae-44cf-a340-87470d5bba62" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_8a1f8801-c4c2-4569-8406-eadee569ae12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_8a1f8801-c4c2-4569-8406-eadee569ae12" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_359003cb-6ef2-4767-aa73-db046106edb5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DividendsCommonStockCash"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_DividendsCommonStockCash_359003cb-6ef2-4767-aa73-db046106edb5" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_fc51dfdf-7c30-4b81-a421-12dc7a602284" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_NetIncomeLoss_fc51dfdf-7c30-4b81-a421-12dc7a602284" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_c1a808a0-9ddc-4359-9146-1592373347a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_c1a808a0-9ddc-4359-9146-1592373347a0" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_72ad4518-4625-4fb9-ab72-11557aa87da0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_72eb8c3d-cad9-43ce-b328-9bfebda70b48" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_72ad4518-4625-4fb9-ab72-11557aa87da0" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_2102de36-48b7-4323-b5ad-78d71a3dc581" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_aaa0f6da-1975-4bfb-a847-5b776af4acf3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_40681089-f40f-4d00-9292-22092830bbe7" xlink:to="loc_us-gaap_StatementTable_aaa0f6da-1975-4bfb-a847-5b776af4acf3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_962b18c1-e05c-42d0-bb04-8cbb404f41d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_aaa0f6da-1975-4bfb-a847-5b776af4acf3" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_962b18c1-e05c-42d0-bb04-8cbb404f41d1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_962b18c1-e05c-42d0-bb04-8cbb404f41d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_962b18c1-e05c-42d0-bb04-8cbb404f41d1" xlink:to="loc_us-gaap_EquityComponentDomain_962b18c1-e05c-42d0-bb04-8cbb404f41d1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_962b18c1-e05c-42d0-bb04-8cbb404f41d1" xlink:to="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_e981473d-edf9-4569-ae32-3f517b892a05" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:to="loc_us-gaap_CommonStockMember_e981473d-edf9-4569-ae32-3f517b892a05" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_8c702e77-dce2-42d7-9c51-96e278c95eb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_8c702e77-dce2-42d7-9c51-96e278c95eb2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_4bf5a960-e932-47f2-a94d-c858bf0445c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:to="loc_us-gaap_RetainedEarningsMember_4bf5a960-e932-47f2-a94d-c858bf0445c8" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a1ed62f4-3d2c-44bd-aea0-71c8d88218b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_a1ed62f4-3d2c-44bd-aea0-71c8d88218b0" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockMember_9be139d2-aa02-47fa-9f64-0e0d99415f80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_02ba3c57-4918-4300-8cb9-6401413a9cd5" xlink:to="loc_us-gaap_TreasuryStockMember_9be139d2-aa02-47fa-9f64-0e0d99415f80" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_4763c6bf-f534-480f-8997-845f2f89fe9f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_aaa0f6da-1975-4bfb-a847-5b776af4acf3" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_4763c6bf-f534-480f-8997-845f2f89fe9f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_4763c6bf-f534-480f-8997-845f2f89fe9f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_4763c6bf-f534-480f-8997-845f2f89fe9f" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_4763c6bf-f534-480f-8997-845f2f89fe9f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_831f23ff-891c-41b1-ae75-854b615b2e32" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_4763c6bf-f534-480f-8997-845f2f89fe9f" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_831f23ff-891c-41b1-ae75-854b615b2e32" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_ba41d83c-09f9-4442-9be9-c9f035bb7dd9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_831f23ff-891c-41b1-ae75-854b615b2e32" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_ba41d83c-09f9-4442-9be9-c9f035bb7dd9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_e10442cc-4a29-41fe-acc0-f2e601046780" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_831f23ff-891c-41b1-ae75-854b615b2e32" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember_e10442cc-4a29-41fe-acc0-f2e601046780" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesTables" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesTables"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesTables" xlink:type="extended" id="icd32e676ead04e5ea28ccbf4e0478f68_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesTables">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock_520d0d29-3aba-462d-82d6-499b3336004b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTableTextBlock_520d0d29-3aba-462d-82d6-499b3336004b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense_4175087b-d6be-42ff-992d-39032a3a82ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense_4175087b-d6be-42ff-992d-39032a3a82ae" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_GrossAndNetCarriedClaimAndClaimAdjustmentExpenseReservesTableTextBlock_78ec918c-467e-447b-82a0-eabf2e85f4f1" xlink:href="cna-20221231.xsd#cna_GrossAndNetCarriedClaimAndClaimAdjustmentExpenseReservesTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_GrossAndNetCarriedClaimAndClaimAdjustmentExpenseReservesTableTextBlock_78ec918c-467e-447b-82a0-eabf2e85f4f1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveAndPremiumDevelopmentTableTextBlock_07163638-baf4-4d0e-bbd5-e23cafe9c90f" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveAndPremiumDevelopmentTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveAndPremiumDevelopmentTableTextBlock_07163638-baf4-4d0e-bbd5-e23cafe9c90f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentTableTextBlock_6b4ef8df-08db-4df3-b5b8-b182f3e540c0" xlink:href="cna-20221231.xsd#cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentTableTextBlock_6b4ef8df-08db-4df3-b5b8-b182f3e540c0" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetIncurredClaimsandAllocatedClaimAdjustmentExpensesTableTextBlock_bdbad583-a9be-4d6d-901d-6b7d21357a3b" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetIncurredClaimsandAllocatedClaimAdjustmentExpensesTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_ShortDurationContractsNetIncurredClaimsandAllocatedClaimAdjustmentExpensesTableTextBlock_bdbad583-a9be-4d6d-901d-6b7d21357a3b" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesReconciliationofTotalLiabilityforUnpaidClaimandClaimAdjustmentExpenseTableTextBlock_d8a3d581-6db3-451d-827c-19c3a8b5a5ac" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesReconciliationofTotalLiabilityforUnpaidClaimandClaimAdjustmentExpenseTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesReconciliationofTotalLiabilityforUnpaidClaimandClaimAdjustmentExpenseTableTextBlock_d8a3d581-6db3-451d-827c-19c3a8b5a5ac" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsReserveDevelopmentTableTextBlock_84f4f961-0be5-43cc-9a76-b39069b2347d" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsReserveDevelopmentTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_ShortDurationContractsReserveDevelopmentTableTextBlock_84f4f961-0be5-43cc-9a76-b39069b2347d" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock_b2c82078-53a3-4c69-8983-b3c897847859" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock_b2c82078-53a3-4c69-8983-b3c897847859" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ImpactOfLossPortfolioTransferOnConsolidatedStatementsOfOperationsTableTextBlock_14bb29bc-2c32-4245-8148-34cb3f30adba" xlink:href="cna-20221231.xsd#cna_ImpactOfLossPortfolioTransferOnConsolidatedStatementsOfOperationsTableTextBlock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_ImpactOfLossPortfolioTransferOnConsolidatedStatementsOfOperationsTableTextBlock_14bb29bc-2c32-4245-8148-34cb3f30adba" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_db273c4c-bc70-4111-8624-224c06ae4e01" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_23795d8d-8883-4b75-b641-86be27d60250" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_db273c4c-bc70-4111-8624-224c06ae4e01" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_db273c4c-bc70-4111-8624-224c06ae4e01" xlink:to="loc_srt_ProductOrServiceAxis_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb" xlink:to="loc_srt_ProductsAndServicesDomain_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_ae0db644-5c30-4c6a-8fef-bd9d3ee41dfb" xlink:to="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_a6235b98-325a-45e2-a812-801e326d9bf8" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_HardyMember_a6235b98-325a-45e2-a812-801e326d9bf8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_7ec9b8fd-86fd-49fd-9528-c08cc6fa5c14" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_7ec9b8fd-86fd-49fd-9528-c08cc6fa5c14" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_9b3669b8-f12d-4c67-8cc3-55762ad55d1c" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_9b3669b8-f12d-4c67-8cc3-55762ad55d1c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_db4fd952-de1c-415e-af04-d38e7960cf92" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_SuretyMember_db4fd952-de1c-415e-af04-d38e7960cf92" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_1f99498f-0a17-4eea-a45c-39e320f0e3f4" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_CommercialAutoProductLineMember_1f99498f-0a17-4eea-a45c-39e320f0e3f4" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_ff0f0fc1-0eb0-406f-a4f9-9af1ee5c1e02" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_us-gaap_GeneralLiabilityMember_ff0f0fc1-0eb0-406f-a4f9-9af1ee5c1e02" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_0c027f64-1813-4c9b-b0cf-1f5eff5d2f58" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_WorkersCompensationMember_0c027f64-1813-4c9b-b0cf-1f5eff5d2f58" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_519d6fa9-04f7-4d08-8650-e43075ff1ad0" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8dfee5f0-3538-4076-83aa-e559dcb27989" xlink:to="loc_cna_ExcludingHardyMember_519d6fa9-04f7-4d08-8650-e43075ff1ad0" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_0b0a0537-984d-4337-8bde-29bd9dc9a975" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_db273c4c-bc70-4111-8624-224c06ae4e01" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_0b0a0537-984d-4337-8bde-29bd9dc9a975" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0b0a0537-984d-4337-8bde-29bd9dc9a975_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0b0a0537-984d-4337-8bde-29bd9dc9a975" xlink:to="loc_us-gaap_SegmentDomain_0b0a0537-984d-4337-8bde-29bd9dc9a975_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0b0a0537-984d-4337-8bde-29bd9dc9a975" xlink:to="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_0cf0e6ed-fe1f-47da-afe8-5461cff8aa8a" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:to="loc_cna_SpecialtySegmentMember_0cf0e6ed-fe1f-47da-afe8-5461cff8aa8a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_d06fae7d-be5b-41a5-b955-2d9538046c58" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:to="loc_cna_CommercialSegmentMember_d06fae7d-be5b-41a5-b955-2d9538046c58" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_164633e2-ca08-4345-894a-ccbb806fbe1a" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:to="loc_cna_InternationalSegmentMember_164633e2-ca08-4345-894a-ccbb806fbe1a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_ae527ea6-3c9a-40d8-b178-18c03b1c921c" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:to="loc_cna_HardyMember_ae527ea6-3c9a-40d8-b178-18c03b1c921c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CNAFConsolidatedMember_d2e58ab8-3482-4d18-944a-7d60e75f0bf6" xlink:href="cna-20221231.xsd#cna_CNAFConsolidatedMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59031860-982c-471e-810c-9db6012b2aa8" xlink:to="loc_cna_CNAFConsolidatedMember_d2e58ab8-3482-4d18-944a-7d60e75f0bf6" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#SummaryofSignificantAccountingPoliciesNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended" id="idc69cd681d6d461399500bb768fc9f27_SummaryofSignificantAccountingPoliciesNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_30be43f8-d2fe-40ab-91c2-7106f4b76a01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_30be43f8-d2fe-40ab-91c2-7106f4b76a01" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_f2cefe72-2567-4112-a303-4a39ab3f2e17" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_StockholdersEquity_f2cefe72-2567-4112-a303-4a39ab3f2e17" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies_cc235ccc-c329-4dd6-8308-cb68d43eb90a" xlink:href="cna-20221231.xsd#cna_AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_AnticipatedAmountsDueFromInsuredsRelatedToLossesUnderDeductiblePolicies_cc235ccc-c329-4dd6-8308-cb68d43eb90a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_StructuredSettlementAnnuitiesInterestRatesLowEnd_5d5a87b0-fc25-467c-a032-151e562219bd" xlink:href="cna-20221231.xsd#cna_StructuredSettlementAnnuitiesInterestRatesLowEnd"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_StructuredSettlementAnnuitiesInterestRatesLowEnd_5d5a87b0-fc25-467c-a032-151e562219bd" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DiscountedReservesForUnfundedStructuredSettlements_ae355d49-a667-494f-8a68-7b55463ebf2c" xlink:href="cna-20221231.xsd#cna_DiscountedReservesForUnfundedStructuredSettlements"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_DiscountedReservesForUnfundedStructuredSettlements_ae355d49-a667-494f-8a68-7b55463ebf2c" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DiscountedReservesForUnfundedStructureSettlementsDiscountAmount_09c3fb22-9e41-4575-b5f4-b88320f2358d" xlink:href="cna-20221231.xsd#cna_DiscountedReservesForUnfundedStructureSettlementsDiscountAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_DiscountedReservesForUnfundedStructureSettlementsDiscountAmount_09c3fb22-9e41-4575-b5f4-b88320f2358d" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements_65739c78-5776-4cee-8c66-19d4b4e9e130" xlink:href="cna-20221231.xsd#cna_Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_Amountofinterestrecognizedonthediscountedreservesofunfundedstructuredsettlements_65739c78-5776-4cee-8c66-19d4b4e9e130" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WorkersCompensationDiscountPercent_024abf98-7b36-4e1d-ae98-33004ba08ab4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WorkersCompensationDiscountPercent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_WorkersCompensationDiscountPercent_024abf98-7b36-4e1d-ae98-33004ba08ab4" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent_458898da-546e-4172-be38-8c46de78acc5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_WorkersCompensationLiabilityCurrentAndNoncurrent_458898da-546e-4172-be38-8c46de78acc5" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WorkersCompensationDiscountAmount_9718533d-a48e-4242-96c4-453c4ba2d94d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WorkersCompensationDiscountAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_WorkersCompensationDiscountAmount_9718533d-a48e-4242-96c4-453c4ba2d94d" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves_2acd0677-3848-4db4-a02c-586c6499ba49" xlink:href="cna-20221231.xsd#cna_Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_Amountofinterestaccretionrecognizedonthediscountedreservesofworkerscompensationlifetimeclaimreserves_2acd0677-3848-4db4-a02c-586c6499ba49" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LongtermCareClaimReservesWeightedAverageDiscountedInterestRate_f038c7de-70dc-42f2-99a1-9bbee04e6351" xlink:href="cna-20221231.xsd#cna_LongtermCareClaimReservesWeightedAverageDiscountedInterestRate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_LongtermCareClaimReservesWeightedAverageDiscountedInterestRate_f038c7de-70dc-42f2-99a1-9bbee04e6351" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Discountedreservesforlongtermcareclaimreserves_78aee2b4-cfae-408c-aec5-0f76e6cf3e0f" xlink:href="cna-20221231.xsd#cna_Discountedreservesforlongtermcareclaimreserves"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_Discountedreservesforlongtermcareclaimreserves_78aee2b4-cfae-408c-aec5-0f76e6cf3e0f" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Discountedreservesforlongtermcareclaimreservesdiscountamount_5859c981-42aa-4c61-82ff-6b7d00cc6e9f" xlink:href="cna-20221231.xsd#cna_Discountedreservesforlongtermcareclaimreservesdiscountamount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_Discountedreservesforlongtermcareclaimreservesdiscountamount_5859c981-42aa-4c61-82ff-6b7d00cc6e9f" xlink:type="arc" order="13"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin_f929dcf0-f0b1-4b7e-9360-fe51ec725eed" xlink:href="cna-20221231.xsd#cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin_f929dcf0-f0b1-4b7e-9360-fe51ec725eed" xlink:type="arc" order="14"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForFuturePolicyBenefitByProductSegmentInterestRateYearOfIssue_685a477c-babf-4434-9813-16d617e10e5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForFuturePolicyBenefitByProductSegmentInterestRateYearOfIssue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_LiabilityForFuturePolicyBenefitByProductSegmentInterestRateYearOfIssue_685a477c-babf-4434-9813-16d617e10e5e" xlink:type="arc" order="15"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability_7776db41-a0ab-4c50-8f26-e54dd9a1ff93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_LossContingencyUndiscountedAmountOfInsuranceRelatedAssessmentLiability_7776db41-a0ab-4c50-8f26-e54dd9a1ff93" xlink:type="arc" order="16"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfBilledReceivablesComparedToTotalReinsuranceReceivable_3603a27e-e1ed-4fc1-bfe7-619507d427d5" xlink:href="cna-20221231.xsd#cna_PercentageOfBilledReceivablesComparedToTotalReinsuranceReceivable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_PercentageOfBilledReceivablesComparedToTotalReinsuranceReceivable_3603a27e-e1ed-4fc1-bfe7-619507d427d5" xlink:type="arc" order="17"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PolicyholderDividendsRateOnPolicyEarnings_281a1152-56e5-4943-a113-1b317ca68f42" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PolicyholderDividendsRateOnPolicyEarnings"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_PolicyholderDividendsRateOnPolicyEarnings_281a1152-56e5-4943-a113-1b317ca68f42" xlink:type="arc" order="18"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Increasedecreaseinshadowadjustmentnetoftax_06531fd5-63d9-4add-8585-54eb74f46d3a" xlink:href="cna-20221231.xsd#cna_Increasedecreaseinshadowadjustmentnetoftax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_Increasedecreaseinshadowadjustmentnetoftax_06531fd5-63d9-4add-8585-54eb74f46d3a" xlink:type="arc" order="19"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ReductionOfNetUnrealizedGainsOnInvestmentsIncludedInAOCIDueToShadowAdjustments_17f41b91-d143-4da0-8b8d-e615abcd40db" xlink:href="cna-20221231.xsd#cna_ReductionOfNetUnrealizedGainsOnInvestmentsIncludedInAOCIDueToShadowAdjustments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_ReductionOfNetUnrealizedGainsOnInvestmentsIncludedInAOCIDueToShadowAdjustments_17f41b91-d143-4da0-8b8d-e615abcd40db" xlink:type="arc" order="20"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WarrantyCoverageTerm_5f558fff-f996-4edd-93bc-2dab661ccb2e" xlink:href="cna-20221231.xsd#cna_WarrantyCoverageTerm"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_cna_WarrantyCoverageTerm_5f558fff-f996-4edd-93bc-2dab661ccb2e" xlink:type="arc" order="21"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_02b36f7e-d169-4ae2-b000-e51de9d02c84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_02b36f7e-d169-4ae2-b000-e51de9d02c84" xlink:type="arc" order="22"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_4f0f8149-26b9-44f7-af10-48bea4567242" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossBeforeTax_4f0f8149-26b9-44f7-af10-48bea4567242" xlink:type="arc" order="23"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_fbcbcb85-170d-4904-84ba-7a79ad61d4af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_fbcbcb85-170d-4904-84ba-7a79ad61d4af" xlink:type="arc" order="24"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_e722b6dd-760a-4d28-b630-f29bf0459494" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_e722b6dd-760a-4d28-b630-f29bf0459494" xlink:type="arc" order="25"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_39b4e1fa-1055-4b0b-8545-fc36d68e9dfa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_39b4e1fa-1055-4b0b-8545-fc36d68e9dfa" xlink:type="arc" order="26"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_f4c725fe-630a-49a3-a2fb-3660abdbbf54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment_f4c725fe-630a-49a3-a2fb-3660abdbbf54" xlink:type="arc" order="27"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_17bb9b91-f0e1-43e5-a6e9-6ef6ee960b7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestPaidNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_InterestPaidNet_17bb9b91-f0e1-43e5-a6e9-6ef6ee960b7a" xlink:type="arc" order="28"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaid_5c34fa54-5092-491b-915f-aee9e08837c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxesPaid"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_IncomeTaxesPaid_5c34fa54-5092-491b-915f-aee9e08837c3" xlink:type="arc" order="29"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleLineItems_c64e3c82-08a2-4fa5-92e1-cc54fcaf114c" xlink:to="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_f87aff51-ddc8-46ee-824b-72306f3f36e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_f87aff51-ddc8-46ee-824b-72306f3f36e7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f87aff51-ddc8-46ee-824b-72306f3f36e7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f87aff51-ddc8-46ee-824b-72306f3f36e7" xlink:to="loc_us-gaap_EquityComponentDomain_f87aff51-ddc8-46ee-824b-72306f3f36e7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_fce3d114-7ba9-45fd-859b-47cb6b19d0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_f87aff51-ddc8-46ee-824b-72306f3f36e7" xlink:to="loc_us-gaap_EquityComponentDomain_fce3d114-7ba9-45fd-859b-47cb6b19d0e9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_ab883faf-1d8c-4aab-8d49-bb9b5f9d59d7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_fce3d114-7ba9-45fd-859b-47cb6b19d0e9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_ab883faf-1d8c-4aab-8d49-bb9b5f9d59d7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_ee613f22-3fd1-4a71-892b-fa390c680a72" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_srt_OwnershipAxis_ee613f22-3fd1-4a71-892b-fa390c680a72" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_ee613f22-3fd1-4a71-892b-fa390c680a72_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_ee613f22-3fd1-4a71-892b-fa390c680a72" xlink:to="loc_srt_OwnershipDomain_ee613f22-3fd1-4a71-892b-fa390c680a72_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_208f5030-29fb-4b80-a289-2d44d00a86ce" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_ee613f22-3fd1-4a71-892b-fa390c680a72" xlink:to="loc_srt_OwnershipDomain_208f5030-29fb-4b80-a289-2d44d00a86ce" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CNAFConsolidatedMember_1def1130-9975-463c-9840-c6bb915ec2eb" xlink:href="cna-20221231.xsd#cna_CNAFConsolidatedMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_208f5030-29fb-4b80-a289-2d44d00a86ce" xlink:to="loc_cna_CNAFConsolidatedMember_1def1130-9975-463c-9840-c6bb915ec2eb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_57d8376e-cc12-4677-8429-35ce5d40d520" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_LegalEntityAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_dei_LegalEntityAxis_57d8376e-cc12-4677-8429-35ce5d40d520" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_57d8376e-cc12-4677-8429-35ce5d40d520_default" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_57d8376e-cc12-4677-8429-35ce5d40d520" xlink:to="loc_dei_EntityDomain_57d8376e-cc12-4677-8429-35ce5d40d520_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_28e179ab-85eb-42e7-8ae3-992330c0e6b4" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_57d8376e-cc12-4677-8429-35ce5d40d520" xlink:to="loc_dei_EntityDomain_28e179ab-85eb-42e7-8ae3-992330c0e6b4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LoewsMember_a135d824-914a-4900-a533-c3b177da47c0" xlink:href="cna-20221231.xsd#cna_LoewsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_28e179ab-85eb-42e7-8ae3-992330c0e6b4" xlink:to="loc_cna_LoewsMember_a135d824-914a-4900-a533-c3b177da47c0" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5a43dd02-cc0a-42b8-931a-5f92d58255b7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_srt_RangeAxis_5a43dd02-cc0a-42b8-931a-5f92d58255b7" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5a43dd02-cc0a-42b8-931a-5f92d58255b7_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5a43dd02-cc0a-42b8-931a-5f92d58255b7" xlink:to="loc_srt_RangeMember_5a43dd02-cc0a-42b8-931a-5f92d58255b7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_fea663da-c4fe-4cf2-9afb-9a1f7a03b881" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5a43dd02-cc0a-42b8-931a-5f92d58255b7" xlink:to="loc_srt_RangeMember_fea663da-c4fe-4cf2-9afb-9a1f7a03b881" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_f60fe629-279a-43e6-a078-e2cea3a07f21" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fea663da-c4fe-4cf2-9afb-9a1f7a03b881" xlink:to="loc_srt_MinimumMember_f60fe629-279a-43e6-a078-e2cea3a07f21" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_a4593244-b53a-4e81-9d24-15df826417b4" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_fea663da-c4fe-4cf2-9afb-9a1f7a03b881" xlink:to="loc_srt_MaximumMember_a4593244-b53a-4e81-9d24-15df826417b4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_cd1b1009-9eda-45e7-9013-b2e69929cb5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_cd1b1009-9eda-45e7-9013-b2e69929cb5c" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cd1b1009-9eda-45e7-9013-b2e69929cb5c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_cd1b1009-9eda-45e7-9013-b2e69929cb5c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_cd1b1009-9eda-45e7-9013-b2e69929cb5c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_963fe47b-b2ae-4d43-8e29-9d666f56a081" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_cd1b1009-9eda-45e7-9013-b2e69929cb5c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_963fe47b-b2ae-4d43-8e29-9d666f56a081" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_45e6104c-2e71-4b4c-b0d1-e204fdbf2359" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FurnitureAndFixturesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_963fe47b-b2ae-4d43-8e29-9d666f56a081" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_45e6104c-2e71-4b4c-b0d1-e204fdbf2359" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OfficeEquipmentMember_211deb2f-8b4d-46af-ba8b-d017c94a3cdb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OfficeEquipmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_963fe47b-b2ae-4d43-8e29-9d666f56a081" xlink:to="loc_us-gaap_OfficeEquipmentMember_211deb2f-8b4d-46af-ba8b-d017c94a3cdb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_ef4bb910-9bb7-499d-b784-d25e43c1d5cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_963fe47b-b2ae-4d43-8e29-9d666f56a081" xlink:to="loc_us-gaap_ComputerSoftwareIntangibleAssetMember_ef4bb910-9bb7-499d-b784-d25e43c1d5cc" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementAxis_e2870d48-718e-491b-a16c-9240957bf8f7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_NewAccountingPronouncementsOrChangeInAccountingPrincipleTable_ff4a945c-fa3d-4843-bae3-3909945e5881" xlink:to="loc_srt_RestatementAxis_e2870d48-718e-491b-a16c-9240957bf8f7" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_e2870d48-718e-491b-a16c-9240957bf8f7_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RestatementAxis_e2870d48-718e-491b-a16c-9240957bf8f7" xlink:to="loc_srt_RestatementDomain_e2870d48-718e-491b-a16c-9240957bf8f7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RestatementDomain_e9de2858-5e97-4259-a461-973a1f72b6ec" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RestatementDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RestatementAxis_e2870d48-718e-491b-a16c-9240957bf8f7" xlink:to="loc_srt_RestatementDomain_e9de2858-5e97-4259-a461-973a1f72b6ec" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RevisionOfPriorPeriodAccountingStandardsUpdateAdjustmentMember_26f82503-8098-4ec4-acc6-fa662481d516" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RevisionOfPriorPeriodAccountingStandardsUpdateAdjustmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RestatementDomain_e9de2858-5e97-4259-a461-973a1f72b6ec" xlink:to="loc_srt_RevisionOfPriorPeriodAccountingStandardsUpdateAdjustmentMember_26f82503-8098-4ec4-acc6-fa662481d516" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsNetinvestmentincomeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsNetinvestmentincomeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsNetinvestmentincomeDetails" xlink:type="extended" id="idc1379d5fe3448e5b5d50787359139bf_InvestmentsNetinvestmentincomeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossInvestmentIncomeOperating_06954d1a-d1b0-42ce-b6bd-451736434465" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GrossInvestmentIncomeOperating"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:to="loc_us-gaap_GrossInvestmentIncomeOperating_06954d1a-d1b0-42ce-b6bd-451736434465" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInvestmentExpense_e6236f6f-75da-45f9-b3ba-ce0fc7010eb2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeInvestmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:to="loc_us-gaap_InvestmentIncomeInvestmentExpense_e6236f6f-75da-45f9-b3ba-ce0fc7010eb2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentIncome_4c437571-081a-4667-8f3c-10558f65fd80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetInvestmentIncome"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:to="loc_us-gaap_NetInvestmentIncome_4c437571-081a-4667-8f3c-10558f65fd80" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_56f195c6-fed8-4efd-9173-cff68e6da791" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_56f195c6-fed8-4efd-9173-cff68e6da791" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_6f7fa797-5686-4739-9914-6cc3b2d72551" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_e5f5b0f2-2d78-4b53-b47b-956cfb6fbfd9" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_6f7fa797-5686-4739-9914-6cc3b2d72551" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_815305c5-8310-4a36-b335-0350a2a82e12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_6f7fa797-5686-4739-9914-6cc3b2d72551" xlink:to="loc_us-gaap_FinancialInstrumentAxis_815305c5-8310-4a36-b335-0350a2a82e12" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_815305c5-8310-4a36-b335-0350a2a82e12_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_815305c5-8310-4a36-b335-0350a2a82e12" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_815305c5-8310-4a36-b335-0350a2a82e12_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_815305c5-8310-4a36-b335-0350a2a82e12" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_16f9b744-926a-43d1-80b5-8a52d4dd2a60" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FixedIncomeSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_FixedIncomeSecuritiesMember_16f9b744-926a-43d1-80b5-8a52d4dd2a60" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_18246479-57af-4e38-a721-f4513fcf4e99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_EquitySecuritiesMember_18246479-57af-4e38-a721-f4513fcf4e99" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedPartnerMember_a559d5b0-7e51-4ec1-b537-f514d595ca56" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LimitedPartnerMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_LimitedPartnerMember_a559d5b0-7e51-4ec1-b537-f514d595ca56" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesMember_c37fadee-1d06-48fd-a9b2-742e17a5e7b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MortgagesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_MortgagesMember_c37fadee-1d06-48fd-a9b2-742e17a5e7b7" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_41eb1aad-b481-4307-a33c-d6be71f55737" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_41eb1aad-b481-4307-a33c-d6be71f55737" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_TradingPortfolioSecuritiesMember_d7856544-7c2b-4e0c-9e70-cb8e4794df79" xlink:href="cna-20221231.xsd#cna_TradingPortfolioSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_cna_TradingPortfolioSecuritiesMember_d7856544-7c2b-4e0c-9e70-cb8e4794df79" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherInvestmentIncomeMember_98ef63ce-b2a4-4624-b767-3abb7c5a6f9f" xlink:href="cna-20221231.xsd#cna_OtherInvestmentIncomeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_cna_OtherInvestmentIncomeMember_98ef63ce-b2a4-4624-b767-3abb7c5a6f9f" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_186744cf-a473-4979-b7ef-0b468a259670" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_CommonStockMember_186744cf-a473-4979-b7ef-0b468a259670" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_4c867e04-e841-422a-b021-165e517e1364" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_690940bc-32cb-4fdd-963d-e37f0dcc8e9c" xlink:to="loc_us-gaap_PreferredStockMember_4c867e04-e841-422a-b021-165e517e1364" xlink:type="arc" order="8"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsNarrativeDetails" xlink:type="extended" id="i33662f45c40b4dcd96390e8553f79202_InvestmentsNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NonIncomeProducingFixedMaturitySecurities_47ca7415-0e8c-4778-b4ba-2112817252d7" xlink:href="cna-20221231.xsd#cna_NonIncomeProducingFixedMaturitySecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_NonIncomeProducingFixedMaturitySecurities_47ca7415-0e8c-4778-b4ba-2112817252d7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NonIncomeProducingMortgageLoans_40bf6dfe-5713-4667-afb6-ed55c46fc486" xlink:href="cna-20221231.xsd#cna_NonIncomeProducingMortgageLoans"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_NonIncomeProducingMortgageLoans_40bf6dfe-5713-4667-afb6-ed55c46fc486" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentsthatExceedTenPercentofStockholdersEquity_b8f6d155-d23d-4a53-9a39-67b55923afe4" xlink:href="cna-20221231.xsd#cna_InvestmentsthatExceedTenPercentofStockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_InvestmentsthatExceedTenPercentofStockholdersEquity_b8f6d155-d23d-4a53-9a39-67b55923afe4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentAndDerivativeRealizedGainLossCoinsuranceAgreement_c080ecf4-438c-4371-a5ac-95646d6b2e93" xlink:href="cna-20221231.xsd#cna_InvestmentAndDerivativeRealizedGainLossCoinsuranceAgreement"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_InvestmentAndDerivativeRealizedGainLossCoinsuranceAgreement_c080ecf4-438c-4371-a5ac-95646d6b2e93" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_3e2b7f6d-11b4-4321-a88d-37777b94c22a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedGain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedGain_3e2b7f6d-11b4-4321-a88d-37777b94c22a" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss_1b7a83a4-e70e-4e92-ad54-87813c022ec4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss_1b7a83a4-e70e-4e92-ad54-87813c022ec4" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealizedInvestmentGainsLosses_b10bcb18-1eeb-49da-b02c-418f409c7135" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealizedInvestmentGainsLosses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_RealizedInvestmentGainsLosses_b10bcb18-1eeb-49da-b02c-418f409c7135" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_2ba77e48-697a-43e9-b205-9b5fc2fdbd32" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_2ba77e48-697a-43e9-b205-9b5fc2fdbd32" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForLoanLossesExpensed_bff4a8b4-995f-4846-abb1-fd155d0afbdc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProvisionForLoanLossesExpensed"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_ProvisionForLoanLossesExpensed_bff4a8b4-995f-4846-abb1-fd155d0afbdc" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax_d04b7b13-9b1f-4015-9a70-e82472d66653" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentBeforeTax_d04b7b13-9b1f-4015-9a70-e82472d66653" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_00745daa-63bd-4ef5-a00f-e7650c15f1d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss_00745daa-63bd-4ef5-a00f-e7650c15f1d1" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LimitedPartnershipInvestments_dc5e49a9-0881-45ba-8267-50216fed3e2a" xlink:href="cna-20221231.xsd#cna_LimitedPartnershipInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_LimitedPartnershipInvestments_dc5e49a9-0881-45ba-8267-50216fed3e2a" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsUndistributedEarningsFromEquityMethodInvestees_12eb37c1-dc67-4400-ae3e-ade338338fc5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsUndistributedEarningsFromEquityMethodInvestees"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_RetainedEarningsUndistributedEarningsFromEquityMethodInvestees_12eb37c1-dc67-4400-ae3e-ade338338fc5" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfLimitedPartnershipsReportedOnCurrentBasis_e847ee0b-811d-4fe7-b40c-1ea6adc05dd7" xlink:href="cna-20221231.xsd#cna_PercentageOfLimitedPartnershipsReportedOnCurrentBasis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_PercentageOfLimitedPartnershipsReportedOnCurrentBasis_e847ee0b-811d-4fe7-b40c-1ea6adc05dd7" xlink:type="arc" order="13"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfLimitedPartnershipsReportedOnOneMonthLag_77db6440-ba68-4ee8-bbc1-bceeeb720625" xlink:href="cna-20221231.xsd#cna_PercentageOfLimitedPartnershipsReportedOnOneMonthLag"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_PercentageOfLimitedPartnershipsReportedOnOneMonthLag_77db6440-ba68-4ee8-bbc1-bceeeb720625" xlink:type="arc" order="14"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LimitedPartnershipsInvestedInPrivateDebtAndEquity_d4413914-7824-419d-a18a-32a10e7677f8" xlink:href="cna-20221231.xsd#cna_LimitedPartnershipsInvestedInPrivateDebtAndEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_LimitedPartnershipsInvestedInPrivateDebtAndEquity_d4413914-7824-419d-a18a-32a10e7677f8" xlink:type="arc" order="15"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments_ee83862d-d197-4423-9905-83ceb4483c0c" xlink:href="cna-20221231.xsd#cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments_ee83862d-d197-4423-9905-83ceb4483c0c" xlink:type="arc" order="16"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CarryingValueOfTenLargestLimitedPartnerships_a21c5afc-3cda-4c71-ad11-2742048eaa8a" xlink:href="cna-20221231.xsd#cna_CarryingValueOfTenLargestLimitedPartnerships"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CarryingValueOfTenLargestLimitedPartnerships_a21c5afc-3cda-4c71-ad11-2742048eaa8a" xlink:type="arc" order="17"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity_aecef795-0d0a-4bfe-8782-9a08c4419165" xlink:href="cna-20221231.xsd#cna_CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity_aecef795-0d0a-4bfe-8782-9a08c4419165" xlink:type="arc" order="18"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships_15a42ee6-e51c-4f6b-9de1-7b9a5e5d562e" xlink:href="cna-20221231.xsd#cna_IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships_15a42ee6-e51c-4f6b-9de1-7b9a5e5d562e" xlink:type="arc" order="19"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeCollateralObligationToReturnCash_bd724c3d-524a-4664-87da-74c47b5f671d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeCollateralObligationToReturnCash"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DerivativeCollateralObligationToReturnCash_bd724c3d-524a-4664-87da-74c47b5f671d" xlink:type="arc" order="20"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_1947635a-8063-461f-8366-a921d4e50f55" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DerivativeLiabilityCollateralRightToReclaimCashOffset_1947635a-8063-461f-8366-a921d4e50f55" xlink:type="arc" order="21"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_0c013d29-7800-4223-b176-ce7403eb552e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DerivativeNotionalAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_DerivativeNotionalAmount_0c013d29-7800-4223-b176-ce7403eb552e" xlink:type="arc" order="22"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_0745a4f6-3eb1-483b-bf6c-ab058ab5b237" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_0745a4f6-3eb1-483b-bf6c-ab058ab5b237" xlink:type="arc" order="23"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncreaseDecreaseFixedMaturitySecurities_fab0fcab-024c-4b4a-8c73-79ec6343c41c" xlink:href="cna-20221231.xsd#cna_IncreaseDecreaseFixedMaturitySecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_IncreaseDecreaseFixedMaturitySecurities_fab0fcab-024c-4b4a-8c73-79ec6343c41c" xlink:type="arc" order="24"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncreaseDecreaseShortTermInvestments_78de3fa5-5a19-478e-852e-17df9345b024" xlink:href="cna-20221231.xsd#cna_IncreaseDecreaseShortTermInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_IncreaseDecreaseShortTermInvestments_78de3fa5-5a19-478e-852e-17df9345b024" xlink:type="arc" order="25"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncreaseDecreaseAccruedInvestmentIncome_e239b937-2bdd-4c77-8932-4a2687b907a6" xlink:href="cna-20221231.xsd#cna_IncreaseDecreaseAccruedInvestmentIncome"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_IncreaseDecreaseAccruedInvestmentIncome_e239b937-2bdd-4c77-8932-4a2687b907a6" xlink:type="arc" order="26"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncreaseDecreaseFundsWithheldLiability_a97c8f39-7ea9-4087-8f44-37c3f351b663" xlink:href="cna-20221231.xsd#cna_IncreaseDecreaseFundsWithheldLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_IncreaseDecreaseFundsWithheldLiability_a97c8f39-7ea9-4087-8f44-37c3f351b663" xlink:type="arc" order="27"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability_1eed52d0-8659-4ff4-b5dd-9c2664957e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_EmbeddedDerivativeFairValueOfEmbeddedDerivativeLiability_1eed52d0-8659-4ff4-b5dd-9c2664957e9b" xlink:type="arc" order="28"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommitmentsToPurchaseOrFundAdditionalAmounts_4a50ea5c-642c-4e14-b7ab-4dac893bf304" xlink:href="cna-20221231.xsd#cna_CommitmentsToPurchaseOrFundAdditionalAmounts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CommitmentsToPurchaseOrFundAdditionalAmounts_4a50ea5c-642c-4e14-b7ab-4dac893bf304" xlink:type="arc" order="29"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommitmentsToSellVariousPrivatelyPlacedDebtSecurities_539bacd2-36ac-434c-b3fa-e7f098b8690f" xlink:href="cna-20221231.xsd#cna_CommitmentsToSellVariousPrivatelyPlacedDebtSecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CommitmentsToSellVariousPrivatelyPlacedDebtSecurities_539bacd2-36ac-434c-b3fa-e7f098b8690f" xlink:type="arc" order="30"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities_f5375b2d-52c2-48c1-88ca-14393531cbfa" xlink:href="cna-20221231.xsd#cna_CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities_f5375b2d-52c2-48c1-88ca-14393531cbfa" xlink:type="arc" order="31"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CashAndSecuritiesDepositedAsCollateralForLettersOfCredit_6a762514-9c8d-4fd1-aec7-b3088026e2b0" xlink:href="cna-20221231.xsd#cna_CashAndSecuritiesDepositedAsCollateralForLettersOfCredit"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_cna_CashAndSecuritiesDepositedAsCollateralForLettersOfCredit_6a762514-9c8d-4fd1-aec7-b3088026e2b0" xlink:type="arc" order="32"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_5950a007-c2ac-4946-bba4-5130c1d581ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss_5950a007-c2ac-4946-bba4-5130c1d581ba" xlink:type="arc" order="33"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_dcbbba1c-aa81-4c30-96a5-2b45d71ba603" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfGainLossOnInvestmentsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems_20871e07-f3c4-4c33-9fd9-b845cdf30339" xlink:to="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_dcbbba1c-aa81-4c30-96a5-2b45d71ba603" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_8b28b819-5992-4c6b-85dd-becbf63b8052" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_dcbbba1c-aa81-4c30-96a5-2b45d71ba603" xlink:to="loc_us-gaap_FinancialInstrumentAxis_8b28b819-5992-4c6b-85dd-becbf63b8052" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8b28b819-5992-4c6b-85dd-becbf63b8052_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_8b28b819-5992-4c6b-85dd-becbf63b8052" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_8b28b819-5992-4c6b-85dd-becbf63b8052_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_8b28b819-5992-4c6b-85dd-becbf63b8052" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_1a2c3ed0-02d0-4324-883a-238aa5d9a2bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_us-gaap_CommonStockMember_1a2c3ed0-02d0-4324-883a-238aa5d9a2bd" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_a293d2e3-1ac4-49f6-a01f-abd949f6fc7c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_us-gaap_PreferredStockMember_a293d2e3-1ac4-49f6-a01f-abd949f6fc7c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_6ad6a059-6ed6-4045-8cb3-acab5469a52e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FixedIncomeSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_us-gaap_FixedIncomeSecuritiesMember_6ad6a059-6ed6-4045-8cb3-acab5469a52e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesMember_a7a3a9c4-4d23-45d9-bd14-2febd06322fe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MortgagesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_us-gaap_MortgagesMember_a7a3a9c4-4d23-45d9-bd14-2febd06322fe" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FundsWithheldLiabilitySecuritiesMember_8029ac8b-8a51-4c21-a214-eee513b7e3f8" xlink:href="cna-20221231.xsd#cna_FundsWithheldLiabilitySecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_cna_FundsWithheldLiabilitySecuritiesMember_8029ac8b-8a51-4c21-a214-eee513b7e3f8" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_5b0dc5ea-f66d-4ef3-9619-71cf949d53e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_9655f422-0b7f-4234-b6db-d85335704496" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_5b0dc5ea-f66d-4ef3-9619-71cf949d53e9" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_cbea749d-c746-485d-ab22-5fb2b076689c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_dcbbba1c-aa81-4c30-96a5-2b45d71ba603" xlink:to="loc_us-gaap_DebtInstrumentAxis_cbea749d-c746-485d-ab22-5fb2b076689c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_cbea749d-c746-485d-ab22-5fb2b076689c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_cbea749d-c746-485d-ab22-5fb2b076689c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_cbea749d-c746-485d-ab22-5fb2b076689c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b67ac1dd-9ec0-45ee-9a94-b15321e4b550" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_cbea749d-c746-485d-ab22-5fb2b076689c" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b67ac1dd-9ec0-45ee-9a94-b15321e4b550" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes5875FaceAmount500DueAugust152020Member_baa7116a-0e34-4952-97ce-128dde4d9ab5" xlink:href="cna-20221231.xsd#cna_SeniorNotes5875FaceAmount500DueAugust152020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b67ac1dd-9ec0-45ee-9a94-b15321e4b550" xlink:to="loc_cna_SeniorNotes5875FaceAmount500DueAugust152020Member_baa7116a-0e34-4952-97ce-128dde4d9ab5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_004e4ce9-5db8-413a-a586-855f4eca70d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGainLossOnInvestmentsTable_dcbbba1c-aa81-4c30-96a5-2b45d71ba603" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_004e4ce9-5db8-413a-a586-855f4eca70d3" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_004e4ce9-5db8-413a-a586-855f4eca70d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_004e4ce9-5db8-413a-a586-855f4eca70d3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_004e4ce9-5db8-413a-a586-855f4eca70d3_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a426659d-1bb7-4600-b32a-493ea1079331" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_004e4ce9-5db8-413a-a586-855f4eca70d3" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a426659d-1bb7-4600-b32a-493ea1079331" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_8a83f10b-3716-4836-929f-3cc49b850392" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorNotesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_a426659d-1bb7-4600-b32a-493ea1079331" xlink:to="loc_us-gaap_SeniorNotesMember_8a83f10b-3716-4836-929f-3cc49b850392" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsComponentsofotherthantemporaryimpairmentlossesrecognizedinearningsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsComponentsofotherthantemporaryimpairmentlossesrecognizedinearningsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsComponentsofotherthantemporaryimpairmentlossesrecognizedinearningsDetails" xlink:type="extended" id="ib95cb747939c4ba78a1d3229639c05c5_InvestmentsComponentsofotherthantemporaryimpairmentlossesrecognizedinearningsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_4e280044-e2ab-4663-8d0c-09dc5c1e942b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings_3fddf035-c703-4bac-9fbb-fbe323ef7f8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_4e280044-e2ab-4663-8d0c-09dc5c1e942b" xlink:to="loc_us-gaap_OtherThanTemporaryImpairmentLossDebtSecuritiesPortionRecognizedInEarnings_3fddf035-c703-4bac-9fbb-fbe323ef7f8c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a39da9c1-f93b-4cf5-902f-e4243d251699" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_4e280044-e2ab-4663-8d0c-09dc5c1e942b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a39da9c1-f93b-4cf5-902f-e4243d251699" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_b1c561d7-0da2-4379-b5e5-9fc4ace95b79" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a39da9c1-f93b-4cf5-902f-e4243d251699" xlink:to="loc_us-gaap_FinancialInstrumentAxis_b1c561d7-0da2-4379-b5e5-9fc4ace95b79" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1c561d7-0da2-4379-b5e5-9fc4ace95b79_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b1c561d7-0da2-4379-b5e5-9fc4ace95b79" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_b1c561d7-0da2-4379-b5e5-9fc4ace95b79_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_68abc6b9-4222-47f9-b634-2b702b181cb8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_b1c561d7-0da2-4379-b5e5-9fc4ace95b79" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_68abc6b9-4222-47f9-b634-2b702b181cb8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_b18faacf-80b4-4d25-9dbc-53cb003376a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_68abc6b9-4222-47f9-b634-2b702b181cb8" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_b18faacf-80b4-4d25-9dbc-53cb003376a7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_93a03750-1574-4a5c-ada5-78040773f301" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_68abc6b9-4222-47f9-b634-2b702b181cb8" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_93a03750-1574-4a5c-ada5-78040773f301" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsSummaryoffixedmaturityandequitysecuritiesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsSummaryoffixedmaturityandequitysecuritiesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsSummaryoffixedmaturityandequitysecuritiesDetails" xlink:type="extended" id="i61af4a93a37a43ef8d96a05729fdf689_InvestmentsSummaryoffixedmaturityandequitysecuritiesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesUnrealizedGainLossAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:to="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_a753bed2-19fa-4140-b17c-499924a95462" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss_a753bed2-19fa-4140-b17c-499924a95462" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_cea24ce2-cc50-4758-924f-04cc0a4f5700" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_cea24ce2-cc50-4758-924f-04cc0a4f5700" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_0fa35c25-250c-44b4-9fbf-47d5950a4f45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_0fa35c25-250c-44b4-9fbf-47d5950a4f45" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_3f592ce8-d6e7-4b57-871c-9d0bbd2d97a5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_3f592ce8-d6e7-4b57-871c-9d0bbd2d97a5" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_961bd710-e7fd-488c-8f9a-48ae786212c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesUnrealizedGainLossAbstract_150a1566-be5f-4f1c-98b9-60ad9b133b15" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest_961bd710-e7fd-488c-8f9a-48ae786212c3" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLossAbstract_84f49d55-f95f-4db5-8043-8d13fa83158e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingGainLossAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:to="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLossAbstract_84f49d55-f95f-4db5-8043-8d13fa83158e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecuritiesDebtAmortizedCost_fc8365df-4707-4655-8ae7-5c9153a48017" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TradingSecuritiesDebtAmortizedCost"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLossAbstract_84f49d55-f95f-4db5-8043-8d13fa83158e" xlink:to="loc_us-gaap_TradingSecuritiesDebtAmortizedCost_fc8365df-4707-4655-8ae7-5c9153a48017" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradingSecuritiesDebt_3f1521d6-8a11-4f43-b6ef-71cd978de55a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TradingSecuritiesDebt"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGainLossAbstract_84f49d55-f95f-4db5-8043-8d13fa83158e" xlink:to="loc_us-gaap_TradingSecuritiesDebt_3f1521d6-8a11-4f43-b6ef-71cd978de55a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtSecuritiesAmortizedCost_842cb329-8b9e-4a3c-ae9a-67b94ed2b7bb" xlink:href="cna-20221231.xsd#cna_DebtSecuritiesAmortizedCost"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:to="loc_cna_DebtSecuritiesAmortizedCost_842cb329-8b9e-4a3c-ae9a-67b94ed2b7bb" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecurities_14ab55a9-a96a-433e-b0ca-4a38d6e45f1c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:to="loc_us-gaap_DebtSecurities_14ab55a9-a96a-433e-b0ca-4a38d6e45f1c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ScheduleOfAvailableForSaleAndTradingSecuritiesTable_c74d329a-b7b9-4252-b943-c0ead25083d2" xlink:href="cna-20221231.xsd#cna_ScheduleOfAvailableForSaleAndTradingSecuritiesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_9f42f367-1a63-4356-af69-6605ef542650" xlink:to="loc_cna_ScheduleOfAvailableForSaleAndTradingSecuritiesTable_c74d329a-b7b9-4252-b943-c0ead25083d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_5260d238-0b45-4a1b-b05c-f3f0870e197e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ScheduleOfAvailableForSaleAndTradingSecuritiesTable_c74d329a-b7b9-4252-b943-c0ead25083d2" xlink:to="loc_us-gaap_FinancialInstrumentAxis_5260d238-0b45-4a1b-b05c-f3f0870e197e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5260d238-0b45-4a1b-b05c-f3f0870e197e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5260d238-0b45-4a1b-b05c-f3f0870e197e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_5260d238-0b45-4a1b-b05c-f3f0870e197e_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_5260d238-0b45-4a1b-b05c-f3f0870e197e" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_e941ded7-91a8-4141-8dfa-c25a801e7ebb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_e941ded7-91a8-4141-8dfa-c25a801e7ebb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_62fbde8f-7797-4107-a9fd-31dc164b6ad8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_62fbde8f-7797-4107-a9fd-31dc164b6ad8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_3e91f411-6523-4eb5-b5a9-d50473e4bdf8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_3e91f411-6523-4eb5-b5a9-d50473e4bdf8" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_083df9d0-e9e7-4c4f-97ba-3919314a44fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_083df9d0-e9e7-4c4f-97ba-3919314a44fa" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_15e5a7e5-3c41-46ca-8512-02dc5005095e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_15e5a7e5-3c41-46ca-8512-02dc5005095e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_0b5cc1a8-6156-4e4d-bcde-3514712797cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_0b5cc1a8-6156-4e4d-bcde-3514712797cf" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_ec960096-109b-45cc-94fe-e23bb638c424" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USTreasuryAndGovernmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_ec960096-109b-45cc-94fe-e23bb638c424" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_c6375fe4-e9ca-47a4-b862-56e435cc70b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_c6375fe4-e9ca-47a4-b862-56e435cc70b5" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemablePreferredStockMember_0c328f7c-57de-43e9-a252-7d2e471053f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RedeemablePreferredStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_d32caf4b-6963-43da-ba09-627c8378cc08" xlink:to="loc_us-gaap_RedeemablePreferredStockMember_0c328f7c-57de-43e9-a252-7d2e471053f3" xlink:type="arc" order="8"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsSecuritiesinagrossunrealizedlosspositionDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsSecuritiesinagrossunrealizedlosspositionDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsSecuritiesinagrossunrealizedlosspositionDetails" xlink:type="extended" id="i1e777cc3fc4145da9cfeec4bf467ac1c_InvestmentsSecuritiesinagrossunrealizedlosspositionDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_05328b73-ef98-4e74-8277-98f6f237bab7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months_05328b73-ef98-4e74-8277-98f6f237bab7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_a5b9abdf-1db1-40e8-81ab-aa2c3cc932b2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_a5b9abdf-1db1-40e8-81ab-aa2c3cc932b2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_e398e2e0-5a35-4c32-bed5-1cdc1c62cdff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger_e398e2e0-5a35-4c32-bed5-1cdc1c62cdff" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_79d29b83-0de9-4634-a62f-73d8f970d272" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_79d29b83-0de9-4634-a62f-73d8f970d272" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_3aec02c8-71e4-4db6-b2d3-c8f39dff6739" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_3aec02c8-71e4-4db6-b2d3-c8f39dff6739" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_deb6cf95-73a8-4143-89de-2e5c258d40a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_deb6cf95-73a8-4143-89de-2e5c258d40a0" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a79535da-9610-49f4-98f4-58e33af84db4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_efbb3023-23e6-4714-9510-952c5fa8d168" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a79535da-9610-49f4-98f4-58e33af84db4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_2afa8396-e619-43df-98b4-1938deb0a088" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_a79535da-9610-49f4-98f4-58e33af84db4" xlink:to="loc_us-gaap_FinancialInstrumentAxis_2afa8396-e619-43df-98b4-1938deb0a088" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2afa8396-e619-43df-98b4-1938deb0a088_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_2afa8396-e619-43df-98b4-1938deb0a088" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_2afa8396-e619-43df-98b4-1938deb0a088_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_2afa8396-e619-43df-98b4-1938deb0a088" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_b7f4ae00-f8dd-413a-84df-1d86a037fd18" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_b7f4ae00-f8dd-413a-84df-1d86a037fd18" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_1ac02759-a037-4176-8f07-253a2fdf254e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_1ac02759-a037-4176-8f07-253a2fdf254e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_1a3accc5-a5b1-4738-a9e1-7effdc4d844d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResidentialMortgageBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_ResidentialMortgageBackedSecuritiesMember_1a3accc5-a5b1-4738-a9e1-7effdc4d844d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_2c0bee1e-ab4e-44aa-93b4-d1e9ddc2bc6e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_CommercialMortgageBackedSecuritiesMember_2c0bee1e-ab4e-44aa-93b4-d1e9ddc2bc6e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_026cfc73-b4bf-476e-8965-95e3c9c55544" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember_026cfc73-b4bf-476e-8965-95e3c9c55544" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_435b44b8-cad1-4295-b6a2-fa8a1e0b5d92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_435b44b8-cad1-4295-b6a2-fa8a1e0b5d92" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_0dc8f8aa-f64a-40a4-8b7f-dce1d7b3a168" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USTreasuryAndGovernmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_0dc8f8aa-f64a-40a4-8b7f-dce1d7b3a168" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_a0455daf-3f9e-4ace-9647-55cecc91ba87" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_04c61b76-292b-4cb9-a3c8-47ac08fa03fb" xlink:to="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember_a0455daf-3f9e-4ace-9647-55cecc91ba87" xlink:type="arc" order="7"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsSecuritiesinagrossunrealizedlosspositionbyratingsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsSecuritiesinagrossunrealizedlosspositionbyratingsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsSecuritiesinagrossunrealizedlosspositionbyratingsDetails" xlink:type="extended" id="i4675885808f847628cfce478847444ba_InvestmentsSecuritiesinagrossunrealizedlosspositionbyratingsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd2b3855-0af9-4361-ab0f-2979939d9d00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_45229ed7-d1c6-4533-adb3-59e595d19c96" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd2b3855-0af9-4361-ab0f-2979939d9d00" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_45229ed7-d1c6-4533-adb3-59e595d19c96" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_74724f94-8d1b-417e-836f-02a76014f1ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd2b3855-0af9-4361-ab0f-2979939d9d00" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss_74724f94-8d1b-417e-836f-02a76014f1ba" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_6a04107c-8e8e-404a-8c9f-be0fdda0c3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_fd2b3855-0af9-4361-ab0f-2979939d9d00" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_6a04107c-8e8e-404a-8c9f-be0fdda0c3b6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingByGroupingAxis_1bdff781-066b-41c0-ab40-98a1d6a9c906" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ExternalCreditRatingByGroupingAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_6a04107c-8e8e-404a-8c9f-be0fdda0c3b6" xlink:to="loc_us-gaap_ExternalCreditRatingByGroupingAxis_1bdff781-066b-41c0-ab40-98a1d6a9c906" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingByGroupingDomain_1bdff781-066b-41c0-ab40-98a1d6a9c906_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ExternalCreditRatingByGroupingDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingAxis_1bdff781-066b-41c0-ab40-98a1d6a9c906" xlink:to="loc_us-gaap_ExternalCreditRatingByGroupingDomain_1bdff781-066b-41c0-ab40-98a1d6a9c906_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ExternalCreditRatingByGroupingDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingAxis_1bdff781-066b-41c0-ab40-98a1d6a9c906" xlink:to="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExternalCreditRatingUSGovernmentGovernmentAgenciesAndGovernmentSponsoredEnterprisesMember_25b8f6da-2301-417d-8720-584fe9a01df4" xlink:href="cna-20221231.xsd#cna_ExternalCreditRatingUSGovernmentGovernmentAgenciesAndGovernmentSponsoredEnterprisesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_cna_ExternalCreditRatingUSGovernmentGovernmentAgenciesAndGovernmentSponsoredEnterprisesMember_25b8f6da-2301-417d-8720-584fe9a01df4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExternalCreditRatingAAAMember_7a697e8a-0808-46b9-a283-99e8abb77762" xlink:href="cna-20221231.xsd#cna_ExternalCreditRatingAAAMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_cna_ExternalCreditRatingAAAMember_7a697e8a-0808-46b9-a283-99e8abb77762" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExternalCreditRatingAAMember_6360df90-3fc8-41fa-83aa-57b7d7becdb4" xlink:href="cna-20221231.xsd#cna_ExternalCreditRatingAAMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_cna_ExternalCreditRatingAAMember_6360df90-3fc8-41fa-83aa-57b7d7becdb4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExternalCreditRatingAMember_8d741ffc-5d28-420f-9383-60dc97f852d0" xlink:href="cna-20221231.xsd#cna_ExternalCreditRatingAMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_cna_ExternalCreditRatingAMember_8d741ffc-5d28-420f-9383-60dc97f852d0" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExternalCreditRatingBBBMember_3bc4c14a-abda-45d9-881c-385089f4f73c" xlink:href="cna-20221231.xsd#cna_ExternalCreditRatingBBBMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_cna_ExternalCreditRatingBBBMember_3bc4c14a-abda-45d9-881c-385089f4f73c" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExternalCreditRatingNonInvestmentGradeMember_b91216dc-b3b4-45c6-a59f-4ec796bfc400" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ExternalCreditRatingNonInvestmentGradeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExternalCreditRatingByGroupingDomain_fe4711d8-d83f-4411-8883-6fa8da5b0fe2" xlink:to="loc_us-gaap_ExternalCreditRatingNonInvestmentGradeMember_b91216dc-b3b4-45c6-a59f-4ec796bfc400" xlink:type="arc" order="5"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsAllowanceonavailableforsalesecuritieswithcreditimpairmentsandPCDassetsactivityDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsAllowanceonavailableforsalesecuritieswithcreditimpairmentsandPCDassetsactivityDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsAllowanceonavailableforsalesecuritieswithcreditimpairmentsandPCDassetsactivityDetails" xlink:type="extended" id="i58fa5321feae448ab7260a51305ff6f5_InvestmentsAllowanceonavailableforsalesecuritieswithcreditimpairmentsandPCDassetsactivityDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_58836f95-a997-4637-ad7a-060b6eb02c81" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bb6f8700-ea62-4d33-b7d6-35bf3269146b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_58836f95-a997-4637-ad7a-060b6eb02c81" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bb6f8700-ea62-4d33-b7d6-35bf3269146b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_733d9290-d372-45d3-9130-84f2f370042b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bb6f8700-ea62-4d33-b7d6-35bf3269146b" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_733d9290-d372-45d3-9130-84f2f370042b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AdditionsToAllowanceForCreditLossesAbstract_f981a8d6-621b-4782-8bde-b6de445b9c75" xlink:href="cna-20221231.xsd#cna_AdditionsToAllowanceForCreditLossesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bb6f8700-ea62-4d33-b7d6-35bf3269146b" xlink:to="loc_cna_AdditionsToAllowanceForCreditLossesAbstract_f981a8d6-621b-4782-8bde-b6de445b9c75" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded_04830684-e0fd-4c2a-9839-f560c8e5cb65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_AdditionsToAllowanceForCreditLossesAbstract_f981a8d6-621b-4782-8bde-b6de445b9c75" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotPreviouslyRecorded_04830684-e0fd-4c2a-9839-f560c8e5cb65" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_48e57bbb-e5c0-4ad7-8f62-f30a1bfe09c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_AdditionsToAllowanceForCreditLossesAbstract_f981a8d6-621b-4782-8bde-b6de445b9c75" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossPurchasedWithCreditDeteriorationIncrease_48e57bbb-e5c0-4ad7-8f62-f30a1bfe09c5" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ReductionsToAllowanceForCreditLossesAbstract_b92fcf65-e038-4d47-b00f-be35889e9574" xlink:href="cna-20221231.xsd#cna_ReductionsToAllowanceForCreditLossesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossRollForward_bb6f8700-ea62-4d33-b7d6-35bf3269146b" xlink:to="loc_cna_ReductionsToAllowanceForCreditLossesAbstract_b92fcf65-e038-4d47-b00f-be35889e9574" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold_e2a87a9a-49ce-4aee-886a-bd734869d84e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ReductionsToAllowanceForCreditLossesAbstract_b92fcf65-e038-4d47-b00f-be35889e9574" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossSecuritiesSold_e2a87a9a-49ce-4aee-886a-bd734869d84e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossWriteoff_953254a2-de82-49cd-a192-b72097aac08d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossWriteoff"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ReductionsToAllowanceForCreditLossesAbstract_b92fcf65-e038-4d47-b00f-be35889e9574" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossWriteoff_953254a2-de82-49cd-a192-b72097aac08d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal_8a8ddb7f-c316-4bab-ab77-f0203a05ffec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ReductionsToAllowanceForCreditLossesAbstract_b92fcf65-e038-4d47-b00f-be35889e9574" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal_8a8ddb7f-c316-4bab-ab77-f0203a05ffec" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest_729d6559-13d2-40b3-9adb-ec5018cdf475" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1052b2e8-979b-4113-ae50-ce2bde84b0f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_58836f95-a997-4637-ad7a-060b6eb02c81" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1052b2e8-979b-4113-ae50-ce2bde84b0f3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_e94b220c-bf69-4bc9-9121-9d748e625ba2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_1052b2e8-979b-4113-ae50-ce2bde84b0f3" xlink:to="loc_us-gaap_FinancialInstrumentAxis_e94b220c-bf69-4bc9-9121-9d748e625ba2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e94b220c-bf69-4bc9-9121-9d748e625ba2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_e94b220c-bf69-4bc9-9121-9d748e625ba2" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e94b220c-bf69-4bc9-9121-9d748e625ba2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c64808b7-4594-485c-957b-6ce17b9d59f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_e94b220c-bf69-4bc9-9121-9d748e625ba2" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c64808b7-4594-485c-957b-6ce17b9d59f9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_a319d168-7a2a-411a-b074-2511eac2009b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c64808b7-4594-485c-957b-6ce17b9d59f9" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_a319d168-7a2a-411a-b074-2511eac2009b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_0e2aa5ba-c799-45f1-a3c6-3f4b13d3e316" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_c64808b7-4594-485c-957b-6ce17b9d59f9" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_0e2aa5ba-c799-45f1-a3c6-3f4b13d3e316" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/InvestmentsCreditqualityindicatorDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#InvestmentsCreditqualityindicatorDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/InvestmentsCreditqualityindicatorDetails" xlink:type="extended" id="i7608473a03654f018ce76e369d61eef2_InvestmentsCreditqualityindicatorDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_79ba791c-9379-4f3f-82c9-0ca6f844c0f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYear_79ba791c-9379-4f3f-82c9-0ca6f844c0f2" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_736f4f2a-3171-46a6-a8e1-9a2047695c95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYear_736f4f2a-3171-46a6-a8e1-9a2047695c95" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_54dbfe84-d6b7-4481-9802-89b8dada1c46" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYear_54dbfe84-d6b7-4481-9802-89b8dada1c46" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_2ec01cd9-e565-4986-adc1-f058a1dceff9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYear_2ec01cd9-e565-4986-adc1-f058a1dceff9" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_e357feb1-1743-4caf-81cd-10d011e295e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYear_e357feb1-1743-4caf-81cd-10d011e295e0" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_55a89fb2-704f-4d96-9bf0-505560f921c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYear_55a89fb2-704f-4d96-9bf0-505560f921c4" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_ff584222-ca3b-4225-b073-a41f5f47f06d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss_ff584222-ca3b-4225-b073-a41f5f47f06d" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_c0841e43-c0c3-4d71-b6de-fab9ed18ea92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_97556463-e497-4a6c-97c7-d9dc63ee6451" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_c0841e43-c0c3-4d71-b6de-fab9ed18ea92" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_6be04603-18fb-4206-a6f7-470454bd77d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_c0841e43-c0c3-4d71-b6de-fab9ed18ea92" xlink:to="loc_us-gaap_FinancialInstrumentAxis_6be04603-18fb-4206-a6f7-470454bd77d1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6be04603-18fb-4206-a6f7-470454bd77d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_6be04603-18fb-4206-a6f7-470454bd77d1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6be04603-18fb-4206-a6f7-470454bd77d1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6878d554-92e3-420b-8689-ee6faaf213a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_6be04603-18fb-4206-a6f7-470454bd77d1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6878d554-92e3-420b-8689-ee6faaf213a2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgagesMember_b65c2165-ae43-41cc-ab19-87858a5387c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MortgagesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_6878d554-92e3-420b-8689-ee6faaf213a2" xlink:to="loc_us-gaap_MortgagesMember_b65c2165-ae43-41cc-ab19-87858a5387c5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageAxis_e39e0638-9cc7-4d92-9009-99121d60f98d" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_c0841e43-c0c3-4d71-b6de-fab9ed18ea92" xlink:to="loc_cna_DebtServiceCoverageAxis_e39e0638-9cc7-4d92-9009-99121d60f98d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageDomain_e39e0638-9cc7-4d92-9009-99121d60f98d_default" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cna_DebtServiceCoverageAxis_e39e0638-9cc7-4d92-9009-99121d60f98d" xlink:to="loc_cna_DebtServiceCoverageDomain_e39e0638-9cc7-4d92-9009-99121d60f98d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageDomain_b0f379ef-50d0-4870-945e-6b144f699860" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cna_DebtServiceCoverageAxis_e39e0638-9cc7-4d92-9009-99121d60f98d" xlink:to="loc_cna_DebtServiceCoverageDomain_b0f379ef-50d0-4870-945e-6b144f699860" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageRatioGreaterThanOrEqualto1.6Member_152e2bf9-8ca4-4774-8cc0-6a83ae0fcfc1" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageRatioGreaterThanOrEqualto1.6Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_DebtServiceCoverageDomain_b0f379ef-50d0-4870-945e-6b144f699860" xlink:to="loc_cna_DebtServiceCoverageRatioGreaterThanOrEqualto1.6Member_152e2bf9-8ca4-4774-8cc0-6a83ae0fcfc1" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageRatioBetween1.2And1.6Member_27c59f6d-86ad-4464-a16a-bf19bf5f1580" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageRatioBetween1.2And1.6Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_DebtServiceCoverageDomain_b0f379ef-50d0-4870-945e-6b144f699860" xlink:to="loc_cna_DebtServiceCoverageRatioBetween1.2And1.6Member_27c59f6d-86ad-4464-a16a-bf19bf5f1580" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtServiceCoverageRatioLessThanOrEqualTo1.2Member_22975a4c-4ba1-4588-b6d9-2eed9be55fd1" xlink:href="cna-20221231.xsd#cna_DebtServiceCoverageRatioLessThanOrEqualTo1.2Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_DebtServiceCoverageDomain_b0f379ef-50d0-4870-945e-6b144f699860" xlink:to="loc_cna_DebtServiceCoverageRatioLessThanOrEqualTo1.2Member_22975a4c-4ba1-4588-b6d9-2eed9be55fd1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanToValueAxis_0ad0d1fd-4490-42ea-8bd1-87cf1951251d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LoanToValueAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_c0841e43-c0c3-4d71-b6de-fab9ed18ea92" xlink:to="loc_us-gaap_LoanToValueAxis_0ad0d1fd-4490-42ea-8bd1-87cf1951251d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanToValueDomain_0ad0d1fd-4490-42ea-8bd1-87cf1951251d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LoanToValueDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LoanToValueAxis_0ad0d1fd-4490-42ea-8bd1-87cf1951251d" xlink:to="loc_us-gaap_LoanToValueDomain_0ad0d1fd-4490-42ea-8bd1-87cf1951251d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoanToValueDomain_46e1eb7f-f110-4795-ac17-b71dd70e2b7d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LoanToValueDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LoanToValueAxis_0ad0d1fd-4490-42ea-8bd1-87cf1951251d" xlink:to="loc_us-gaap_LoanToValueDomain_46e1eb7f-f110-4795-ac17-b71dd70e2b7d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtToValueRatioLessThan55PercentMember_9f2a07e5-4455-4e34-9b0e-e800be9d2a94" xlink:href="cna-20221231.xsd#cna_DebtToValueRatioLessThan55PercentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanToValueDomain_46e1eb7f-f110-4795-ac17-b71dd70e2b7d" xlink:to="loc_cna_DebtToValueRatioLessThan55PercentMember_9f2a07e5-4455-4e34-9b0e-e800be9d2a94" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtToValueRatioEqualTo55To65PercentMember_beac0e19-a18b-4244-a0c7-52255de578b0" xlink:href="cna-20221231.xsd#cna_DebtToValueRatioEqualTo55To65PercentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanToValueDomain_46e1eb7f-f110-4795-ac17-b71dd70e2b7d" xlink:to="loc_cna_DebtToValueRatioEqualTo55To65PercentMember_beac0e19-a18b-4244-a0c7-52255de578b0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DebtToValueRatioGreaterThan65PercentMember_98ee33cd-faa4-4edb-855b-4de56b2159f2" xlink:href="cna-20221231.xsd#cna_DebtToValueRatioGreaterThan65PercentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LoanToValueDomain_46e1eb7f-f110-4795-ac17-b71dd70e2b7d" xlink:to="loc_cna_DebtToValueRatioGreaterThan65PercentMember_98ee33cd-faa4-4edb-855b-4de56b2159f2" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/FairValueAssetsandliabilitiesmeasuredatfairvalueonarecurringbasisDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#FairValueAssetsandliabilitiesmeasuredatfairvalueonarecurringbasisDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/FairValueAssetsandliabilitiesmeasuredatfairvalueonarecurringbasisDetails" xlink:type="extended" id="i7ce3cd41d8464099ade9620cb81b5c2c_FairValueAssetsandliabilitiesmeasuredatfairvalueonarecurringbasisDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAbstract_ecca5b39-e3a3-45e8-b316-1ce7dd9a0656" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_DebtSecuritiesAbstract_ecca5b39-e3a3-45e8-b316-1ce7dd9a0656" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecurities_3ce73367-4712-49a8-be43-3fc4f13f79bf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtSecuritiesAbstract_ecca5b39-e3a3-45e8-b316-1ce7dd9a0656" xlink:to="loc_us-gaap_DebtSecurities_3ce73367-4712-49a8-be43-3fc4f13f79bf" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsAbstract_b7577173-28ec-4771-92e1-16205c837c3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_ShortTermInvestmentsAbstract_b7577173-28ec-4771-92e1-16205c837c3a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_70026b73-2062-43c9-87dd-1c47a2e0ff23" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNi"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermInvestmentsAbstract_b7577173-28ec-4771-92e1-16205c837c3a" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_70026b73-2062-43c9-87dd-1c47a2e0ff23" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShorttermInvestmentsandOther_187a3da6-d3c9-4b16-8060-f5d489664e51" xlink:href="cna-20221231.xsd#cna_ShorttermInvestmentsandOther"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_cna_ShorttermInvestmentsandOther_187a3da6-d3c9-4b16-8060-f5d489664e51" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_fff1684c-5586-42e2-a629-d8e7937787a8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsFairValueDisclosure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_fff1684c-5586-42e2-a629-d8e7937787a8" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_51400b4e-55ce-4b35-af52-13c254bc5e99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilitiesFairValueDisclosure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_OtherLiabilitiesFairValueDisclosure_51400b4e-55ce-4b35-af52-13c254bc5e99" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_e45b55de-00b3-451d-88eb-5441a394929c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_e45b55de-00b3-451d-88eb-5441a394929c" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_800e6ad1-26b6-4ce5-9826-a048ad8eab6a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f4828799-bfe6-4b00-8cc0-b33800bae946" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_800e6ad1-26b6-4ce5-9826-a048ad8eab6a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_19417be2-9198-4a79-922e-947f2461610e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_800e6ad1-26b6-4ce5-9826-a048ad8eab6a" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_19417be2-9198-4a79-922e-947f2461610e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19417be2-9198-4a79-922e-947f2461610e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_19417be2-9198-4a79-922e-947f2461610e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_19417be2-9198-4a79-922e-947f2461610e_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83bd65d6-f3ed-4bbc-b4a6-0c7d409be123" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_19417be2-9198-4a79-922e-947f2461610e" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83bd65d6-f3ed-4bbc-b4a6-0c7d409be123" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_1080d09f-a4d1-4d91-9c7c-717762b656f4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83bd65d6-f3ed-4bbc-b4a6-0c7d409be123" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_1080d09f-a4d1-4d91-9c7c-717762b656f4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_561048b9-05a7-4c4a-a971-9d54371a6957" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83bd65d6-f3ed-4bbc-b4a6-0c7d409be123" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_561048b9-05a7-4c4a-a971-9d54371a6957" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_1387b8f2-83e8-4fff-ad82-afbbf5bfc95a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_83bd65d6-f3ed-4bbc-b4a6-0c7d409be123" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_1387b8f2-83e8-4fff-ad82-afbbf5bfc95a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_e38de5c2-2407-4e5e-8521-b479745d3011" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_800e6ad1-26b6-4ce5-9826-a048ad8eab6a" xlink:to="loc_us-gaap_FinancialInstrumentAxis_e38de5c2-2407-4e5e-8521-b479745d3011" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e38de5c2-2407-4e5e-8521-b479745d3011_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_e38de5c2-2407-4e5e-8521-b479745d3011" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e38de5c2-2407-4e5e-8521-b479745d3011_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_e38de5c2-2407-4e5e-8521-b479745d3011" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_ca383408-16b8-4c86-bdf8-197420638310" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_ca383408-16b8-4c86-bdf8-197420638310" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_556c9b01-5182-41e5-91e8-5c00e0ba3ed7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_556c9b01-5182-41e5-91e8-5c00e0ba3ed7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_39c7ddb8-060b-4195-90bc-eea8ab19af2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_39c7ddb8-060b-4195-90bc-eea8ab19af2f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_9fb0bf41-bf1a-4664-943c-1b3b2037b457" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:to="loc_us-gaap_CommonStockMember_9fb0bf41-bf1a-4664-943c-1b3b2037b457" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_0f08bc1d-5dcb-4121-8589-e31d95d85e03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_e78fce70-e205-4265-98be-a3da1fa3da5e" xlink:to="loc_us-gaap_PreferredStockMember_0f08bc1d-5dcb-4121-8589-e31d95d85e03" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/FairValueTableofreconciliationforassetsandliabilitiesmeasuredatfairvalueonarecurringbasisusingsignificantunobservableinputsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#FairValueTableofreconciliationforassetsandliabilitiesmeasuredatfairvalueonarecurringbasisusingsignificantunobservableinputsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/FairValueTableofreconciliationforassetsandliabilitiesmeasuredatfairvalueonarecurringbasisusingsignificantunobservableinputsDetails" xlink:type="extended" id="i2b9225c25af748058da6e783d3e6b0d7_FairValueTableofreconciliationforassetsandliabilitiesmeasuredatfairvalueonarecurringbasisusingsignificantunobservableinputsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b1d292b6-4401-4f60-8942-4d9b442ccb76" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b1d292b6-4401-4f60-8942-4d9b442ccb76" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_8a8f0a16-f007-4d54-a40c-968bc59be8e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_8a8f0a16-f007-4d54-a40c-968bc59be8e6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_f7a13ecc-a1be-4733-bf52-a4ea2a731187" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_f7a13ecc-a1be-4733-bf52-a4ea2a731187" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList_47a5a2b5-7124-40c8-9cbc-1d514cbab957" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleList_47a5a2b5-7124-40c8-9cbc-1d514cbab957" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome_d91b531d-719a-44d2-b280-aa73a9b448e0" xlink:href="cna-20221231.xsd#cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedinNetInvestmentIncome_d91b531d-719a-44d2-b280-aa73a9b448e0" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfOtherComprehensiveIncomeExtensibleList_8b19c188-1c8a-455c-8a0e-ef262683d95d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfOtherComprehensiveIncomeExtensibleList"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfOtherComprehensiveIncomeExtensibleList_8b19c188-1c8a-455c-8a0e-ef262683d95d" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_1a606b11-77ed-4dc8-8973-56cdb7da73a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_1a606b11-77ed-4dc8-8973-56cdb7da73a6" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss_80f12281-e760-40bc-9a20-6d70dc267b4e" xlink:href="cna-20221231.xsd#cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarningsAndOtherComprehensiveIncomeLoss_80f12281-e760-40bc-9a20-6d70dc267b4e" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_f12868c1-b8a9-4012-b253-61c3eb4b17b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_f12868c1-b8a9-4012-b253-61c3eb4b17b7" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_3a6a3a04-fcb9-422d-b66b-718261de43f1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_3a6a3a04-fcb9-422d-b66b-718261de43f1" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_fceb0b7e-a7ae-491f-a915-154631a8125d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_fceb0b7e-a7ae-491f-a915-154631a8125d" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_fb2c3c08-8190-4ba8-b5d2-f4fd048fd318" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersIntoLevel3_fb2c3c08-8190-4ba8-b5d2-f4fd048fd318" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_b99251ba-3a04-43a4-8143-190dc2ecfb50" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_7161ad89-559d-4b63-b713-bc9f97287620" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_b99251ba-3a04-43a4-8143-190dc2ecfb50" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_0409ce0a-77da-446f-b388-2144f964f353" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_02184306-2079-4100-84dd-f582980630f8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b1d292b6-4401-4f60-8942-4d9b442ccb76" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisChangeInUnrealizedGainLoss_02184306-2079-4100-84dd-f582980630f8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss_7be1d018-d986-493a-ae9c-4e6cede88558" xlink:href="cna-20221231.xsd#cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b1d292b6-4401-4f60-8942-4d9b442ccb76" xlink:to="loc_cna_FairValueMeasurementwithUnobservableInputsReconciliationRecurringBasisAssetUnrealizedGainLossIncludedinOtherComprehensiveIncomeLoss_7be1d018-d986-493a-ae9c-4e6cede88558" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_d5bac6f0-8c6c-4ca0-9716-2d2ea287102e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_b1d292b6-4401-4f60-8942-4d9b442ccb76" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_d5bac6f0-8c6c-4ca0-9716-2d2ea287102e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_d5bac6f0-8c6c-4ca0-9716-2d2ea287102e" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3151aa82-1180-4978-91e5-c1e1ddea2ef2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_f08c0ea6-c9d5-4173-bf6c-8af30e631fb3" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3151aa82-1180-4978-91e5-c1e1ddea2ef2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherRevenuesMember_49c3f871-85c2-407f-a8f7-edd2055f695b" xlink:href="cna-20221231.xsd#cna_OtherRevenuesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3151aa82-1180-4978-91e5-c1e1ddea2ef2" xlink:to="loc_cna_OtherRevenuesMember_49c3f871-85c2-407f-a8f7-edd2055f695b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_b9ce2a3d-5afe-4f65-bf50-57daba256e00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByAssetClassAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_d5bac6f0-8c6c-4ca0-9716-2d2ea287102e" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_b9ce2a3d-5afe-4f65-bf50-57daba256e00" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_b9ce2a3d-5afe-4f65-bf50-57daba256e00_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_b9ce2a3d-5afe-4f65-bf50-57daba256e00" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_b9ce2a3d-5afe-4f65-bf50-57daba256e00_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_b9ce2a3d-5afe-4f65-bf50-57daba256e00" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_d98a8036-ee5c-458e-b962-840696dcb6a3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_d98a8036-ee5c-458e-b962-840696dcb6a3" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_9e075e54-5ee5-4707-b8f3-798af4b000a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_9e075e54-5ee5-4707-b8f3-798af4b000a6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_154d81d9-6b6a-45d9-a29c-2087b971d4c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_154d81d9-6b6a-45d9-a29c-2087b971d4c3" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_7c7b641b-305b-4f11-a93b-082cb4f80820" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_09ebd445-8052-4868-a51c-c6ad17af8b03" xlink:to="loc_us-gaap_EquitySecuritiesMember_7c7b641b-305b-4f11-a93b-082cb4f80820" xlink:type="arc" order="3"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/FairValueQuantitativeinformationaboutsignificantunobservableinputsinthefairvaluemeasurementoflevel3assetsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#FairValueQuantitativeinformationaboutsignificantunobservableinputsinthefairvaluemeasurementoflevel3assetsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/FairValueQuantitativeinformationaboutsignificantunobservableinputsinthefairvaluemeasurementoflevel3assetsDetails" xlink:type="extended" id="i0ec2bc4a21e24573af20d2bc8a23becd_FairValueQuantitativeinformationaboutsignificantunobservableinputsinthefairvaluemeasurementoflevel3assetsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_1ae13282-3e47-40c1-99da-efc61c4f2ee9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_9cca355d-4d6f-4696-b287-a90d23832a3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsFairValueDisclosure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_1ae13282-3e47-40c1-99da-efc61c4f2ee9" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_9cca355d-4d6f-4696-b287-a90d23832a3a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_7a8d14c5-a237-4745-adcd-e034c9639326" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_1ae13282-3e47-40c1-99da-efc61c4f2ee9" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleMeasurementInput_7a8d14c5-a237-4745-adcd-e034c9639326" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_1ae13282-3e47-40c1-99da-efc61c4f2ee9" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_c078fed9-2213-44bd-982d-48e83f81a7da" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_c078fed9-2213-44bd-982d-48e83f81a7da" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_c078fed9-2213-44bd-982d-48e83f81a7da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_c078fed9-2213-44bd-982d-48e83f81a7da" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_c078fed9-2213-44bd-982d-48e83f81a7da_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_b63a4651-3fcd-4e6f-ac3c-d824100914ce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_c078fed9-2213-44bd-982d-48e83f81a7da" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_b63a4651-3fcd-4e6f-ac3c-d824100914ce" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputCreditSpreadMember_bd124020-c45a-4911-ab8e-de8beb1a4b3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MeasurementInputCreditSpreadMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_b63a4651-3fcd-4e6f-ac3c-d824100914ce" xlink:to="loc_us-gaap_MeasurementInputCreditSpreadMember_bd124020-c45a-4911-ab8e-de8beb1a4b3b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_ad0a084b-a7f0-4691-bc11-01432fd75cb4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByAssetClassAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_ad0a084b-a7f0-4691-bc11-01432fd75cb4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_ad0a084b-a7f0-4691-bc11-01432fd75cb4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_ad0a084b-a7f0-4691-bc11-01432fd75cb4" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_ad0a084b-a7f0-4691-bc11-01432fd75cb4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_53b810a0-eb35-4c7c-ab02-e0a074712a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_ad0a084b-a7f0-4691-bc11-01432fd75cb4" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_53b810a0-eb35-4c7c-ab02-e0a074712a8e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember_132dca8c-fb22-495e-959d-7d2a9f26926a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FixedIncomeSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_53b810a0-eb35-4c7c-ab02-e0a074712a8e" xlink:to="loc_us-gaap_FixedIncomeSecuritiesMember_132dca8c-fb22-495e-959d-7d2a9f26926a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueAxis_f3b2c8df-f2b8-42c0-9a52-1a892573d38c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationTechniqueAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:to="loc_us-gaap_ValuationTechniqueAxis_f3b2c8df-f2b8-42c0-9a52-1a892573d38c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_f3b2c8df-f2b8-42c0-9a52-1a892573d38c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationTechniqueDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationTechniqueAxis_f3b2c8df-f2b8-42c0-9a52-1a892573d38c" xlink:to="loc_us-gaap_ValuationTechniqueDomain_f3b2c8df-f2b8-42c0-9a52-1a892573d38c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDomain_a25bf57a-699a-4ec1-b456-a1582f4052e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationTechniqueDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationTechniqueAxis_f3b2c8df-f2b8-42c0-9a52-1a892573d38c" xlink:to="loc_us-gaap_ValuationTechniqueDomain_a25bf57a-699a-4ec1-b456-a1582f4052e0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_be56f810-9561-4df6-a898-0b37e9e19ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationTechniqueDiscountedCashFlowMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationTechniqueDomain_a25bf57a-699a-4ec1-b456-a1582f4052e0" xlink:to="loc_us-gaap_ValuationTechniqueDiscountedCashFlowMember_be56f810-9561-4df6-a898-0b37e9e19ec6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b3086d0c-41ec-4f97-b371-58da20bbff4b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_7d573f99-1e00-4768-be5a-e9ee06f70cf1" xlink:to="loc_srt_RangeAxis_b3086d0c-41ec-4f97-b371-58da20bbff4b" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b3086d0c-41ec-4f97-b371-58da20bbff4b_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b3086d0c-41ec-4f97-b371-58da20bbff4b" xlink:to="loc_srt_RangeMember_b3086d0c-41ec-4f97-b371-58da20bbff4b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d4e49491-1c36-4768-9b9a-60332382f910" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b3086d0c-41ec-4f97-b371-58da20bbff4b" xlink:to="loc_srt_RangeMember_d4e49491-1c36-4768-9b9a-60332382f910" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_e6f423fc-3402-4b13-a7b5-c53c46386d8f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d4e49491-1c36-4768-9b9a-60332382f910" xlink:to="loc_srt_MinimumMember_e6f423fc-3402-4b13-a7b5-c53c46386d8f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_44382822-a5ba-4834-a620-baaa901c8ff9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d4e49491-1c36-4768-9b9a-60332382f910" xlink:to="loc_srt_MaximumMember_44382822-a5ba-4834-a620-baaa901c8ff9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_c0f58c65-b852-4081-a49f-6ee2af130135" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_WeightedAverageMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d4e49491-1c36-4768-9b9a-60332382f910" xlink:to="loc_srt_WeightedAverageMember_c0f58c65-b852-4081-a49f-6ee2af130135" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/FairValueCarryingamountandestimatedfairvalueoffinancialinstrumentassetsandliabilitieswhicharenotmeasuredatfairvalueDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#FairValueCarryingamountandestimatedfairvalueoffinancialinstrumentassetsandliabilitieswhicharenotmeasuredatfairvalueDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/FairValueCarryingamountandestimatedfairvalueoffinancialinstrumentassetsandliabilitieswhicharenotmeasuredatfairvalueDetails" xlink:type="extended" id="i1280e6a4437c41c4ba14158aae4283d6_FairValueCarryingamountandestimatedfairvalueoffinancialinstrumentassetsandliabilitieswhicharenotmeasuredatfairvalueDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_aa4e1bf7-6a1c-4eea-b1b9-71560dda68c6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_8aa48876-ff02-4ce6-95bc-4daf12fb8e0c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_aa4e1bf7-6a1c-4eea-b1b9-71560dda68c6" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_8aa48876-ff02-4ce6-95bc-4daf12fb8e0c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_b8bcc5b0-92ce-417b-aff9-c40ebe33e90c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_8aa48876-ff02-4ce6-95bc-4daf12fb8e0c" xlink:to="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_b8bcc5b0-92ce-417b-aff9-c40ebe33e90c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_abc0abd1-d5f8-4f71-9970-568576ed1b64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_aa4e1bf7-6a1c-4eea-b1b9-71560dda68c6" xlink:to="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_abc0abd1-d5f8-4f71-9970-568576ed1b64" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShorttermDebtFairValue_1e26157c-2783-4d7d-8770-61f5270a5ffa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShorttermDebtFairValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_abc0abd1-d5f8-4f71-9970-568576ed1b64" xlink:to="loc_us-gaap_ShorttermDebtFairValue_1e26157c-2783-4d7d-8770-61f5270a5ffa" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_2a644d04-53b7-4353-b286-f6f3857e8ede" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_abc0abd1-d5f8-4f71-9970-568576ed1b64" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_2a644d04-53b7-4353-b286-f6f3857e8ede" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_174088e7-44c6-40b3-89bf-c849dbcff155" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_aa4e1bf7-6a1c-4eea-b1b9-71560dda68c6" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_174088e7-44c6-40b3-89bf-c849dbcff155" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0d4bd6d3-f4eb-4288-b094-c06cf180550f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_174088e7-44c6-40b3-89bf-c849dbcff155" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0d4bd6d3-f4eb-4288-b094-c06cf180550f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_0d4bd6d3-f4eb-4288-b094-c06cf180550f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0d4bd6d3-f4eb-4288-b094-c06cf180550f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_0d4bd6d3-f4eb-4288-b094-c06cf180550f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2202d5d3-043b-4b2f-af4b-1c822010f3b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_0d4bd6d3-f4eb-4288-b094-c06cf180550f" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2202d5d3-043b-4b2f-af4b-1c822010f3b7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_75c4764e-7407-480d-86ab-6fe40c5f856e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2202d5d3-043b-4b2f-af4b-1c822010f3b7" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_75c4764e-7407-480d-86ab-6fe40c5f856e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_3336d5e8-de8b-4e77-b271-55908c423164" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2202d5d3-043b-4b2f-af4b-1c822010f3b7" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_3336d5e8-de8b-4e77-b271-55908c423164" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_41b0650e-f18e-49f6-a84a-cf2f57a31ee4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_2202d5d3-043b-4b2f-af4b-1c822010f3b7" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_41b0650e-f18e-49f6-a84a-cf2f57a31ee4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_66dd33e9-f908-4baf-aaac-6677ee02dcd2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_174088e7-44c6-40b3-89bf-c849dbcff155" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_66dd33e9-f908-4baf-aaac-6677ee02dcd2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_66dd33e9-f908-4baf-aaac-6677ee02dcd2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_66dd33e9-f908-4baf-aaac-6677ee02dcd2" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_66dd33e9-f908-4baf-aaac-6677ee02dcd2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_84bf7404-5b9a-4fb8-a0ae-3cf6fe34669b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_66dd33e9-f908-4baf-aaac-6677ee02dcd2" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_84bf7404-5b9a-4fb8-a0ae-3cf6fe34669b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b74f68cc-898e-4a50-9da5-1b7b2afe8f29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_84bf7404-5b9a-4fb8-a0ae-3cf6fe34669b" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b74f68cc-898e-4a50-9da5-1b7b2afe8f29" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_630feac9-72fa-4569-91fc-6e731718b127" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b74f68cc-898e-4a50-9da5-1b7b2afe8f29" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_630feac9-72fa-4569-91fc-6e731718b127" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_d34cb679-4dc6-48e8-a82a-175b72b84a38" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_b74f68cc-898e-4a50-9da5-1b7b2afe8f29" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_d34cb679-4dc6-48e8-a82a-175b72b84a38" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#IncomeTaxesNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended" id="i286209ffcaed474e8e3c2ff0bd738d98_IncomeTaxesNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_5b6d9675-9961-4833-aadc-9b22cc886436" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_5b6d9675-9961-4833-aadc-9b22cc886436" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_36fc178b-8cd2-4c7f-b9e1-dd8b74fa1cf9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefits"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_36fc178b-8cd2-4c7f-b9e1-dd8b74fa1cf9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_ec9df0e7-0957-45ab-bfb5-ae2d1d435347" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestIncomeExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_ec9df0e7-0957-45ab-bfb5-ae2d1d435347" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense_05d06586-3ee1-4643-b76c-45a75ec222d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesExpense_05d06586-3ee1-4643-b76c-45a75ec222d5" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_a2252d5a-a20e-4a31-9b9e-19cd5af4709d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_a2252d5a-a20e-4a31-9b9e-19cd5af4709d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries_c9b51cb7-55b4-42a9-a37c-dde3c603bb3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_DeferredTaxLiabilityNotRecognizedAmountOfUnrecognizedDeferredTaxLiabilityUndistributedEarningsOfForeignSubsidiaries_c9b51cb7-55b4-42a9-a37c-dde3c603bb3b" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_3eb55941-c77c-4d2e-a2cc-ec7e56c43ae6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_ForeignIncomeTaxExpenseBenefitContinuingOperations_3eb55941-c77c-4d2e-a2cc-ec7e56c43ae6" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_d9b7491a-d666-421e-b089-55d9ca3a3a71" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign_d9b7491a-d666-421e-b089-55d9ca3a3a71" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentForeignTaxExpenseBenefit_94c5a46a-9145-4c26-8487-41ed64bf79c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CurrentForeignTaxExpenseBenefit"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_CurrentForeignTaxExpenseBenefit_94c5a46a-9145-4c26-8487-41ed64bf79c5" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_0e57e9e8-30b9-4567-94e9-1d3784e8f084" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLossCarryforwards"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_OperatingLossCarryforwards_0e57e9e8-30b9-4567-94e9-1d3784e8f084" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardAmount_c53c94ff-1bc3-4a4c-9981-c4f16f5c2fc7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TaxCreditCarryforwardAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_TaxCreditCarryforwardAmount_c53c94ff-1bc3-4a4c-9981-c4f16f5c2fc7" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_b0652ebe-83d0-47a3-a3f3-10b13c146886" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_b0652ebe-83d0-47a3-a3f3-10b13c146886" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_5d676ea9-3433-4ff2-b033-9cfc6c9abfb9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxContingencyTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_99402eaf-0896-4a4c-97ac-f92dff286efa" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_5d676ea9-3433-4ff2-b033-9cfc6c9abfb9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_f6d24c36-4e76-431f-86bc-94cd452ca094" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_5d676ea9-3433-4ff2-b033-9cfc6c9abfb9" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_f6d24c36-4e76-431f-86bc-94cd452ca094" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_f6d24c36-4e76-431f-86bc-94cd452ca094_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_f6d24c36-4e76-431f-86bc-94cd452ca094" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_f6d24c36-4e76-431f-86bc-94cd452ca094_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_417d685b-4030-43e3-a8e5-90ba26c2bb92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxAuthorityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_f6d24c36-4e76-431f-86bc-94cd452ca094" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_417d685b-4030-43e3-a8e5-90ba26c2bb92" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_51b6e9a2-166d-4d82-9bdb-bec290cc0a4e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForeignCountryMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_417d685b-4030-43e3-a8e5-90ba26c2bb92" xlink:to="loc_us-gaap_ForeignCountryMember_51b6e9a2-166d-4d82-9bdb-bec290cc0a4e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_fafd3500-c1fb-4f1f-bb0e-10ac76991f26" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_5d676ea9-3433-4ff2-b033-9cfc6c9abfb9" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_fafd3500-c1fb-4f1f-bb0e-10ac76991f26" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_fafd3500-c1fb-4f1f-bb0e-10ac76991f26_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_fafd3500-c1fb-4f1f-bb0e-10ac76991f26" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_fafd3500-c1fb-4f1f-bb0e-10ac76991f26_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_f0a737f3-e289-45c6-afe8-bf3ff3b7fd92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_fafd3500-c1fb-4f1f-bb0e-10ac76991f26" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_f0a737f3-e289-45c6-afe8-bf3ff3b7fd92" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FederalIncomeTaxesMember_05a93fd6-d69f-4364-87cc-ed1a69af313a" xlink:href="cna-20221231.xsd#cna_FederalIncomeTaxesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_f0a737f3-e289-45c6-afe8-bf3ff3b7fd92" xlink:to="loc_cna_FederalIncomeTaxesMember_05a93fd6-d69f-4364-87cc-ed1a69af313a" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesReconciliationofLiabilityforUnpaidClaimandClaimAdjustmentExpenseDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesReconciliationofLiabilityforUnpaidClaimandClaimAdjustmentExpenseDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesReconciliationofLiabilityforUnpaidClaimandClaimAdjustmentExpenseDetails" xlink:type="extended" id="i561824da34424e52b8ef2f7eaa3ed3c3_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesReconciliationofLiabilityforUnpaidClaimandClaimAdjustmentExpenseDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c5f1f5d9-fbee-4f54-9482-c93c5f3996f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_5be8fab2-b1cd-4f02-9db2-43cc65731db4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c5f1f5d9-fbee-4f54-9482-c93c5f3996f0" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_5be8fab2-b1cd-4f02-9db2-43cc65731db4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesOnUnpaidLossesGross_13f3d6ee-fac7-427e-8619-42922be88ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsuranceRecoverablesOnUnpaidLossesGross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c5f1f5d9-fbee-4f54-9482-c93c5f3996f0" xlink:to="loc_us-gaap_ReinsuranceRecoverablesOnUnpaidLossesGross_13f3d6ee-fac7-427e-8619-42922be88ac7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_3c0ae8f9-9f70-45da-892f-fe519f996f5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c5f1f5d9-fbee-4f54-9482-c93c5f3996f0" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_3c0ae8f9-9f70-45da-892f-fe519f996f5c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_08d31512-e3df-4654-9489-c7dd0c63c107" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c5f1f5d9-fbee-4f54-9482-c93c5f3996f0" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_08d31512-e3df-4654-9489-c7dd0c63c107" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_08d31512-e3df-4654-9489-c7dd0c63c107" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b" xlink:to="loc_us-gaap_SegmentDomain_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_95cb6d5d-9a29-4028-a9f4-2cdd0b275e9b" xlink:to="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_207c5343-4c32-4274-9107-56c5f75d200d" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:to="loc_cna_SpecialtySegmentMember_207c5343-4c32-4274-9107-56c5f75d200d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_2d0e0656-2aba-4ce9-b57c-cbcc2d73da56" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:to="loc_cna_CommercialSegmentMember_2d0e0656-2aba-4ce9-b57c-cbcc2d73da56" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_e7c37b5f-4e40-42a6-bf39-2968406f897b" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:to="loc_cna_InternationalSegmentMember_e7c37b5f-4e40-42a6-bf39-2968406f897b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LifeandGroupMember_440e8cc8-2976-43e2-a5ed-d594da0902af" xlink:href="cna-20221231.xsd#cna_LifeandGroupMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:to="loc_cna_LifeandGroupMember_440e8cc8-2976-43e2-a5ed-d594da0902af" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_be1523b5-d9ee-4651-89a2-ad84cb02cade" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_176c23f3-346c-4ac5-829b-8ef9aa404c9f" xlink:to="loc_us-gaap_CorporateAndOtherMember_be1523b5-d9ee-4651-89a2-ad84cb02cade" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesGrossandNetCarriedClaimandClaimAdjustmentExpenseReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesGrossandNetCarriedClaimandClaimAdjustmentExpenseReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesGrossandNetCarriedClaimandClaimAdjustmentExpenseReservesDetails" xlink:type="extended" id="i294d33758765493581ff1f77134cddd7_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesGrossandNetCarriedClaimandClaimAdjustmentExpenseReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount_be7ea4ee-f01d-4414-b006-c8ba645d9c40" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseReportedClaimsAmount_be7ea4ee-f01d-4414-b006-c8ba645d9c40" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount_632842f7-9a58-4d91-b011-dc0ccfc682d8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount_632842f7-9a58-4d91-b011-dc0ccfc682d8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Liabilityforunpaidclaimandclaimadjustmentexpensegross_44818778-451b-4d87-a827-79f6653ff444" xlink:href="cna-20221231.xsd#cna_Liabilityforunpaidclaimandclaimadjustmentexpensegross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_cna_Liabilityforunpaidclaimandclaimadjustmentexpensegross_44818778-451b-4d87-a827-79f6653ff444" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetCaseReserves_ac9905f8-f62e-49b2-b10b-56bc32532c44" xlink:href="cna-20221231.xsd#cna_NetCaseReserves"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_cna_NetCaseReserves_ac9905f8-f62e-49b2-b10b-56bc32532c44" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIbnrReserves_3816e889-2731-485c-8b56-e6e98db44ec3" xlink:href="cna-20221231.xsd#cna_NetIbnrReserves"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_cna_NetIbnrReserves_3816e889-2731-485c-8b56-e6e98db44ec3" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_45a0240e-33a1-417e-bea6-e39a83eb510f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_45a0240e-33a1-417e-bea6-e39a83eb510f" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a60e34f0-482e-4c32-bfc0-6ef85f035f55" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_4d8ab0a8-d20b-4ed9-8ac5-be2280ae0271" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a60e34f0-482e-4c32-bfc0-6ef85f035f55" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_fffdda43-3d20-4d61-8a2d-582470b254c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a60e34f0-482e-4c32-bfc0-6ef85f035f55" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_fffdda43-3d20-4d61-8a2d-582470b254c2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fffdda43-3d20-4d61-8a2d-582470b254c2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fffdda43-3d20-4d61-8a2d-582470b254c2" xlink:to="loc_us-gaap_SegmentDomain_fffdda43-3d20-4d61-8a2d-582470b254c2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fffdda43-3d20-4d61-8a2d-582470b254c2" xlink:to="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_db1153c7-9e28-4989-af7f-f0c41ad9647e" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:to="loc_cna_SpecialtySegmentMember_db1153c7-9e28-4989-af7f-f0c41ad9647e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_8d46c31b-7ce0-41a8-8b7b-cfa6f2cf1161" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:to="loc_cna_CommercialSegmentMember_8d46c31b-7ce0-41a8-8b7b-cfa6f2cf1161" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_5f768840-7b56-4db3-b0b0-0add6f587ac8" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:to="loc_cna_InternationalSegmentMember_5f768840-7b56-4db3-b0b0-0add6f587ac8" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LifeAndGroupNonCoreSegmentMember_3db34dfc-9f73-4124-83e4-acf81fa82f6f" xlink:href="cna-20221231.xsd#cna_LifeAndGroupNonCoreSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:to="loc_cna_LifeAndGroupNonCoreSegmentMember_3db34dfc-9f73-4124-83e4-acf81fa82f6f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_eb367f47-8c67-4b59-a844-594b4a1ca5e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_054a19e7-f358-48c9-9a34-ac46298c50e8" xlink:to="loc_us-gaap_CorporateAndOtherMember_eb367f47-8c67-4b59-a844-594b4a1ca5e1" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNetPriorYearDevelopmentDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNetPriorYearDevelopmentDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNetPriorYearDevelopmentDetails" xlink:type="extended" id="i92b97265b1ee416c9fa100a2587e3e40_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNetPriorYearDevelopmentDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_95303e93-000d-4d3a-b02a-a6b087156a21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup_8f407c2e-d4bc-40e1-9cc0-f820ce441a4b" xlink:href="cna-20221231.xsd#cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_95303e93-000d-4d3a-b02a-a6b087156a21" xlink:to="loc_cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup_8f407c2e-d4bc-40e1-9cc0-f820ce441a4b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5e263f63-de03-48fb-a313-20a01acf39ff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_95303e93-000d-4d3a-b02a-a6b087156a21" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5e263f63-de03-48fb-a313-20a01acf39ff" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7808776f-7b4d-4a75-b0f9-e36b8e65a113" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5e263f63-de03-48fb-a313-20a01acf39ff" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7808776f-7b4d-4a75-b0f9-e36b8e65a113" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7808776f-7b4d-4a75-b0f9-e36b8e65a113_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7808776f-7b4d-4a75-b0f9-e36b8e65a113" xlink:to="loc_us-gaap_SegmentDomain_7808776f-7b4d-4a75-b0f9-e36b8e65a113_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7808776f-7b4d-4a75-b0f9-e36b8e65a113" xlink:to="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_349e7c41-f34d-4879-9b0c-f332682042b4" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:to="loc_cna_SpecialtySegmentMember_349e7c41-f34d-4879-9b0c-f332682042b4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_8a2b3cca-becb-4c2c-acf4-31d18d4178ae" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:to="loc_cna_CommercialSegmentMember_8a2b3cca-becb-4c2c-acf4-31d18d4178ae" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_ea7fe015-2185-4752-b03d-e120f7378f5b" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:to="loc_cna_InternationalSegmentMember_ea7fe015-2185-4752-b03d-e120f7378f5b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_f3701b41-c3ea-4f39-8d99-56e3f45faee4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3bd82644-a501-4c57-899d-070647c00af5" xlink:to="loc_us-gaap_CorporateAndOtherMember_f3701b41-c3ea-4f39-8d99-56e3f45faee4" xlink:type="arc" order="3"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNarrativeDetails" xlink:type="extended" id="id3e6c205625841eab5c18687aa0e4b17_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup_9484fb2d-0eb1-4903-b3ec-473de6cd8174" xlink:href="cna-20221231.xsd#cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_PretaxFavorableUnfavorablePremiumDevelopmentExcludingLifeGroup_9484fb2d-0eb1-4903-b3ec-473de6cd8174" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForAsbestosAndEnvironmentalClaimsNet_ee24cb43-8a5d-484c-b390-c7311c6205a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForAsbestosAndEnvironmentalClaimsNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_LiabilityForAsbestosAndEnvironmentalClaimsNet_ee24cb43-8a5d-484c-b390-c7311c6205a7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AggregateLimitUnderAepLossPortfolioTransfer_bd9f72fd-118b-4501-869d-8653866fac42" xlink:href="cna-20221231.xsd#cna_AggregateLimitUnderAepLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_AggregateLimitUnderAepLossPortfolioTransfer_bd9f72fd-118b-4501-869d-8653866fac42" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ClaimAndAllocatedClaimAdjustmentExpenseReservesUnderExistingThirdPartyReinsuranceContracts_459a7f80-07fc-46d1-84f4-02da583ffa51" xlink:href="cna-20221231.xsd#cna_ClaimAndAllocatedClaimAdjustmentExpenseReservesUnderExistingThirdPartyReinsuranceContracts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_ClaimAndAllocatedClaimAdjustmentExpenseReservesUnderExistingThirdPartyReinsuranceContracts_459a7f80-07fc-46d1-84f4-02da583ffa51" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ReinsurancePremiumPaidToNicoUnderAepLossPortfolioTransfer_3dc26fb7-edc9-4f28-9242-fae9f89c1180" xlink:href="cna-20221231.xsd#cna_ReinsurancePremiumPaidToNicoUnderAepLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_ReinsurancePremiumPaidToNicoUnderAepLossPortfolioTransfer_3dc26fb7-edc9-4f28-9242-fae9f89c1180" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetreinsurancereceivablestransferredtoNICOunderAEPLossPortfolioTransfer_3e54ee9d-6d26-46a8-895c-88ae1341e2c5" xlink:href="cna-20221231.xsd#cna_NetreinsurancereceivablestransferredtoNICOunderAEPLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_NetreinsurancereceivablestransferredtoNICOunderAEPLossPortfolioTransfer_3e54ee9d-6d26-46a8-895c-88ae1341e2c5" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_TotalconsiderationpaidtoNICOunderAEPLossPortfolioTransfer_f36a9d87-f55c-4b2e-af65-99311e5b4767" xlink:href="cna-20221231.xsd#cna_TotalconsiderationpaidtoNICOunderAEPLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_TotalconsiderationpaidtoNICOunderAEPLossPortfolioTransfer_f36a9d87-f55c-4b2e-af65-99311e5b4767" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetAEPadversedevelopmentbeforeconsiderationofLPT_ee5a1a41-4103-4e35-844b-b51e1e200a71" xlink:href="cna-20221231.xsd#cna_NetAEPadversedevelopmentbeforeconsiderationofLPT"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_NetAEPadversedevelopmentbeforeconsiderationofLPT_ee5a1a41-4103-4e35-844b-b51e1e200a71" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ProvisionForUncollectibleThirdPartyReinsuranceReleased_dd405966-776d-4acd-83e5-9b448739d6af" xlink:href="cna-20221231.xsd#cna_ProvisionForUncollectibleThirdPartyReinsuranceReleased"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_ProvisionForUncollectibleThirdPartyReinsuranceReleased_dd405966-776d-4acd-83e5-9b448739d6af" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CumulativeamountscededunderAEPLossPortfolioTransfer_a0ba5763-0527-4380-982e-0d94f08347bb" xlink:href="cna-20221231.xsd#cna_CumulativeamountscededunderAEPLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_CumulativeamountscededunderAEPLossPortfolioTransfer_a0ba5763-0527-4380-982e-0d94f08347bb" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Deferredreinsurancebenefityettoberecognized_f4fe1c09-e01a-4249-8dc4-1f88189bb6c8" xlink:href="cna-20221231.xsd#cna_Deferredreinsurancebenefityettoberecognized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_Deferredreinsurancebenefityettoberecognized_f4fe1c09-e01a-4249-8dc4-1f88189bb6c8" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer_bcd295eb-a855-4ce8-80e0-9c11a251f2cb" xlink:href="cna-20221231.xsd#cna_FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_FairValueOfCollateralTrustAccountEstablishedByNicoUnderAepLossPortfolioTransfer_bcd295eb-a855-4ce8-80e0-9c11a251f2cb" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FundsHeldUnderReinsuranceAgreementsLiability_e5c9c085-387c-41c7-9819-c84bb7569c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FundsHeldUnderReinsuranceAgreementsLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_FundsHeldUnderReinsuranceAgreementsLiability_e5c9c085-387c-41c7-9819-c84bb7569c5b" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_RetroactiveReinsuranceAgreementMaximum_e654b05e-bda5-4933-8f94-0c21d9cc9a9e" xlink:href="cna-20221231.xsd#cna_RetroactiveReinsuranceAgreementMaximum"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_RetroactiveReinsuranceAgreementMaximum_e654b05e-bda5-4933-8f94-0c21d9cc9a9e" xlink:type="arc" order="13"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ReinsurancePremiumsPaid_c80a9ee4-9c10-4b28-9f93-bb6e477014a4" xlink:href="cna-20221231.xsd#cna_ReinsurancePremiumsPaid"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_ReinsurancePremiumsPaid_c80a9ee4-9c10-4b28-9f93-bb6e477014a4" xlink:type="arc" order="14"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceLossOnUncollectibleAccountsInPeriodAmount_69713cb3-8637-4de3-b05a-0b9d83c38471" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsuranceLossOnUncollectibleAccountsInPeriodAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_ReinsuranceLossOnUncollectibleAccountsInPeriodAmount_69713cb3-8637-4de3-b05a-0b9d83c38471" xlink:type="arc" order="15"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuritiesHeldAsCollateralAtFairValue_d1e918dd-f3a5-468a-a89a-61d945f8d1c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuritiesHeldAsCollateralAtFairValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_SecuritiesHeldAsCollateralAtFairValue_d1e918dd-f3a5-468a-a89a-61d945f8d1c8" xlink:type="arc" order="16"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease_de1dc0ee-7eb6-4aa1-9991-6d97dc034e65" xlink:href="cna-20221231.xsd#cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease_de1dc0ee-7eb6-4aa1-9991-6d97dc034e65" xlink:type="arc" order="17"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount_35b40422-c431-49fa-913a-8ade7ab0bf84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredButNotReportedIBNRClaimsAmount_35b40422-c431-49fa-913a-8ade7ab0bf84" xlink:type="arc" order="18"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimSeverityAdjustmentPeriodIncreaseDecrease_878c2a71-49ee-45b4-9710-e206881babee" xlink:href="cna-20221231.xsd#cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimSeverityAdjustmentPeriodIncreaseDecrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimSeverityAdjustmentPeriodIncreaseDecrease_878c2a71-49ee-45b4-9710-e206881babee" xlink:type="arc" order="19"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease_7d4e3f3a-ce51-4112-8438-7438f7cb8ff3" xlink:href="cna-20221231.xsd#cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease_7d4e3f3a-ce51-4112-8438-7438f7cb8ff3" xlink:type="arc" order="20"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin_340cb319-a759-494d-b976-b91d0ff30d0f" xlink:href="cna-20221231.xsd#cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin_340cb319-a759-494d-b976-b91d0ff30d0f" xlink:type="arc" order="21"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_11a3afa2-d640-4f0a-94ee-69db1832f16a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_cf238e44-20a3-4676-b16a-4e6141142b72" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_11a3afa2-d640-4f0a-94ee-69db1832f16a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_d35903c1-4327-4290-9242-efd47062782c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_11a3afa2-d640-4f0a-94ee-69db1832f16a" xlink:to="loc_srt_ProductOrServiceAxis_d35903c1-4327-4290-9242-efd47062782c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d35903c1-4327-4290-9242-efd47062782c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_d35903c1-4327-4290-9242-efd47062782c" xlink:to="loc_srt_ProductsAndServicesDomain_d35903c1-4327-4290-9242-efd47062782c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1d874007-cccc-44b7-abb6-8baa57d71c5c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_d35903c1-4327-4290-9242-efd47062782c" xlink:to="loc_srt_ProductsAndServicesDomain_1d874007-cccc-44b7-abb6-8baa57d71c5c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AsbestosandEnvironmentalReservesMember_b7006c34-a305-4287-a82b-b6e57086e28d" xlink:href="cna-20221231.xsd#cna_AsbestosandEnvironmentalReservesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1d874007-cccc-44b7-abb6-8baa57d71c5c" xlink:to="loc_cna_AsbestosandEnvironmentalReservesMember_b7006c34-a305-4287-a82b-b6e57086e28d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcessWorkersCompensationLPTMember_e1ea9394-57df-4332-89fb-71d6c8d4d84d" xlink:href="cna-20221231.xsd#cna_ExcessWorkersCompensationLPTMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1d874007-cccc-44b7-abb6-8baa57d71c5c" xlink:to="loc_cna_ExcessWorkersCompensationLPTMember_e1ea9394-57df-4332-89fb-71d6c8d4d84d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c48316d2-8f94-4900-ac09-acab6db36c64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_11a3afa2-d640-4f0a-94ee-69db1832f16a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c48316d2-8f94-4900-ac09-acab6db36c64" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c48316d2-8f94-4900-ac09-acab6db36c64_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c48316d2-8f94-4900-ac09-acab6db36c64" xlink:to="loc_us-gaap_SegmentDomain_c48316d2-8f94-4900-ac09-acab6db36c64_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0ec79393-9bfc-4dd6-a1bb-5f64ec64e21a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c48316d2-8f94-4900-ac09-acab6db36c64" xlink:to="loc_us-gaap_SegmentDomain_0ec79393-9bfc-4dd6-a1bb-5f64ec64e21a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_8a40abf1-b1d7-4b61-b4fa-9bbb2532143c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0ec79393-9bfc-4dd6-a1bb-5f64ec64e21a" xlink:to="loc_us-gaap_CorporateAndOtherMember_8a40abf1-b1d7-4b61-b4fa-9bbb2532143c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_09a15074-bda5-41fb-b7be-37841edf9c8e" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0ec79393-9bfc-4dd6-a1bb-5f64ec64e21a" xlink:to="loc_cna_CommercialSegmentMember_09a15074-bda5-41fb-b7be-37841edf9c8e" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails" xlink:type="extended" id="ie0a61b43f24443eaaad4cdbb05de127a_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability_71e325c8-69aa-4abd-9c0f-4f08e6625a81" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability_71e325c8-69aa-4abd-9c0f-4f08e6625a81" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability_912a5da3-0b72-44c7-abb3-677072e8b2d3" xlink:href="cna-20221231.xsd#cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability_912a5da3-0b72-44c7-abb3-677072e8b2d3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety_48334a13-d704-4fda-86a9-737ca84a03c0" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety_48334a13-d704-4fda-86a9-737ca84a03c0" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty_61a68369-c1ca-4fe1-a2b1-27b459443716" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWarranty_61a68369-c1ca-4fe1-a2b1-27b459443716" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther_47d3f799-f759-4b3a-9416-d13f99f466cd" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentOther_47d3f799-f759-4b3a-9416-d13f99f466cd" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_f1e71b5d-e2d9-412e-b86e-fc72dbad21f0" xlink:href="cna-20221231.xsd#cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_f1e71b5d-e2d9-412e-b86e-fc72dbad21f0" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a1691108-1f42-445c-9042-98aeda46dafe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5e74ab28-c661-4ba2-b3c1-3716eef91e66" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a1691108-1f42-445c-9042-98aeda46dafe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_210916bb-d90f-496f-811f-e72dc519f1d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_a1691108-1f42-445c-9042-98aeda46dafe" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_210916bb-d90f-496f-811f-e72dc519f1d4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_210916bb-d90f-496f-811f-e72dc519f1d4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_210916bb-d90f-496f-811f-e72dc519f1d4" xlink:to="loc_us-gaap_SegmentDomain_210916bb-d90f-496f-811f-e72dc519f1d4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fbe32cd3-759d-4f07-ad9a-f262446525aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_210916bb-d90f-496f-811f-e72dc519f1d4" xlink:to="loc_us-gaap_SegmentDomain_fbe32cd3-759d-4f07-ad9a-f262446525aa" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_f463ed39-39d1-4f82-bf03-4881a1b49c28" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_fbe32cd3-759d-4f07-ad9a-f262446525aa" xlink:to="loc_cna_SpecialtySegmentMember_f463ed39-39d1-4f82-bf03-4881a1b49c28" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyLineofBusinessCompositionDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyLineofBusinessCompositionDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyLineofBusinessCompositionDetails" xlink:type="extended" id="ic654a3445de4401f949be05fe4af4474_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyLineofBusinessCompositionDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_eb56d54b-ecd6-47ff-af21-528444881152" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_9da556c0-d213-4453-b81d-be9efb027fc1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_eb56d54b-ecd6-47ff-af21-528444881152" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_9da556c0-d213-4453-b81d-be9efb027fc1" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_f869b3a2-9ee9-401f-92c1-b84a4ae5a18f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_eb56d54b-ecd6-47ff-af21-528444881152" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_f869b3a2-9ee9-401f-92c1-b84a4ae5a18f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8556bbb6-706c-4feb-84dc-2aa8d64820fd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_f869b3a2-9ee9-401f-92c1-b84a4ae5a18f" xlink:to="loc_srt_ProductOrServiceAxis_8556bbb6-706c-4feb-84dc-2aa8d64820fd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8556bbb6-706c-4feb-84dc-2aa8d64820fd_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8556bbb6-706c-4feb-84dc-2aa8d64820fd" xlink:to="loc_srt_ProductsAndServicesDomain_8556bbb6-706c-4feb-84dc-2aa8d64820fd_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8556bbb6-706c-4feb-84dc-2aa8d64820fd" xlink:to="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_80113251-c5e5-4128-84f6-ded6a5593aff" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_80113251-c5e5-4128-84f6-ded6a5593aff" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_ddd974e9-32dc-4667-b488-e04bc36e26b5" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_ddd974e9-32dc-4667-b488-e04bc36e26b5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_3229caae-31e9-4517-952b-18aaa0ce47b3" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:to="loc_cna_SuretyMember_3229caae-31e9-4517-952b-18aaa0ce47b3" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WarrantyMember_dee89b03-0b9d-4996-8c29-8efef5f9e410" xlink:href="cna-20221231.xsd#cna_WarrantyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:to="loc_cna_WarrantyMember_dee89b03-0b9d-4996-8c29-8efef5f9e410" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherMember_e82924ff-d8f6-4e9c-887f-31d2ad7bf1c7" xlink:href="cna-20221231.xsd#cna_OtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_4a94f513-5137-4504-ad4e-6e61c8878a85" xlink:to="loc_cna_OtherMember_e82924ff-d8f6-4e9c-887f-31d2ad7bf1c7" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_fd99b269-cb85-4348-aa1b-4acf8f70262f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_f869b3a2-9ee9-401f-92c1-b84a4ae5a18f" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_fd99b269-cb85-4348-aa1b-4acf8f70262f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fd99b269-cb85-4348-aa1b-4acf8f70262f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fd99b269-cb85-4348-aa1b-4acf8f70262f" xlink:to="loc_us-gaap_SegmentDomain_fd99b269-cb85-4348-aa1b-4acf8f70262f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_8a4465f9-955e-48f2-bf5f-c89fb3439486" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fd99b269-cb85-4348-aa1b-4acf8f70262f" xlink:to="loc_us-gaap_SegmentDomain_8a4465f9-955e-48f2-bf5f-c89fb3439486" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_933da30a-78b9-4503-9164-a24d11d65e23" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_8a4465f9-955e-48f2-bf5f-c89fb3439486" xlink:to="loc_cna_SpecialtySegmentMember_933da30a-78b9-4503-9164-a24d11d65e23" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityCumulativeNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityCumulativeNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityCumulativeNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="i827d34c6410e4b329659154c8b60a1a9_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityCumulativeNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_5dc8bfdc-4dd6-4e80-a472-4730c921ce40" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_2d1e6053-f379-4521-9e7c-eb077381442f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_5dc8bfdc-4dd6-4e80-a472-4730c921ce40" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_2d1e6053-f379-4521-9e7c-eb077381442f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_6c812e14-beab-41f0-8163-53b58f56c09b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_5dc8bfdc-4dd6-4e80-a472-4730c921ce40" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_6c812e14-beab-41f0-8163-53b58f56c09b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_0160c8eb-f56d-48b4-9491-d04ab783d58d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_5dc8bfdc-4dd6-4e80-a472-4730c921ce40" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_0160c8eb-f56d-48b4-9491-d04ab783d58d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a3ff548e-df5a-4ec4-96b6-323b3a17ef51" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_5dc8bfdc-4dd6-4e80-a472-4730c921ce40" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a3ff548e-df5a-4ec4-96b6-323b3a17ef51" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_f921f5c4-e372-43af-ab03-c48fd5c8dc6d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a3ff548e-df5a-4ec4-96b6-323b3a17ef51" xlink:to="loc_srt_ProductOrServiceAxis_f921f5c4-e372-43af-ab03-c48fd5c8dc6d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f921f5c4-e372-43af-ab03-c48fd5c8dc6d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_f921f5c4-e372-43af-ab03-c48fd5c8dc6d" xlink:to="loc_srt_ProductsAndServicesDomain_f921f5c4-e372-43af-ab03-c48fd5c8dc6d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3f11adf1-50d0-41ae-aa63-1c4b212b22cd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_f921f5c4-e372-43af-ab03-c48fd5c8dc6d" xlink:to="loc_srt_ProductsAndServicesDomain_3f11adf1-50d0-41ae-aa63-1c4b212b22cd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_f15aebda-35e1-4892-b1a8-53ece6b41c90" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_3f11adf1-50d0-41ae-aa63-1c4b212b22cd" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_f15aebda-35e1-4892-b1a8-53ece6b41c90" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_61bc7b69-14ae-4726-8e18-bc61d497de83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a3ff548e-df5a-4ec4-96b6-323b3a17ef51" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_61bc7b69-14ae-4726-8e18-bc61d497de83" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_61bc7b69-14ae-4726-8e18-bc61d497de83_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_61bc7b69-14ae-4726-8e18-bc61d497de83" xlink:to="loc_us-gaap_SegmentDomain_61bc7b69-14ae-4726-8e18-bc61d497de83_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_153ff659-41d2-4ea5-bf2e-a59ffc7bca00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_61bc7b69-14ae-4726-8e18-bc61d497de83" xlink:to="loc_us-gaap_SegmentDomain_153ff659-41d2-4ea5-bf2e-a59ffc7bca00" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_6a0938a6-2dcd-49c8-a7a0-a88d7a940339" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_153ff659-41d2-4ea5-bf2e-a59ffc7bca00" xlink:to="loc_cna_SpecialtySegmentMember_6a0938a6-2dcd-49c8-a7a0-a88d7a940339" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e6214b88-8c8a-42a7-8d53-bd5e590c89b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a3ff548e-df5a-4ec4-96b6-323b3a17ef51" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e6214b88-8c8a-42a7-8d53-bd5e590c89b1" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e6214b88-8c8a-42a7-8d53-bd5e590c89b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e6214b88-8c8a-42a7-8d53-bd5e590c89b1" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e6214b88-8c8a-42a7-8d53-bd5e590c89b1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e6214b88-8c8a-42a7-8d53-bd5e590c89b1" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_c2accd6b-71ad-4192-8c9d-911e11873a9d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_c2accd6b-71ad-4192-8c9d-911e11873a9d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_2cda96c0-65ce-4943-adc5-8eb2339b319d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_2cda96c0-65ce-4943-adc5-8eb2339b319d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_92201f21-728f-4d9a-ac86-a1d8c80af030" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_92201f21-728f-4d9a-ac86-a1d8c80af030" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e3c6f479-79fe-44a2-9d9e-3544d90a5f4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e3c6f479-79fe-44a2-9d9e-3544d90a5f4c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_5a1ad6c5-3ebc-4702-b6ad-12cb2947b075" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_5a1ad6c5-3ebc-4702-b6ad-12cb2947b075" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_7e69f918-b150-437c-9163-eb73c41a9195" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_7e69f918-b150-437c-9163-eb73c41a9195" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_ddf28ece-b139-4dc1-b389-4134e84795c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_ddf28ece-b139-4dc1-b389-4134e84795c1" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_bb6d01c7-a62a-4a4d-bbf5-f3c5e8510931" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_bb6d01c7-a62a-4a4d-bbf5-f3c5e8510931" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_fcb2da73-03d9-4f03-837a-7060ee5de7c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_fcb2da73-03d9-4f03-837a-7060ee5de7c9" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_1a6cd6c1-b172-483b-88bd-8254208faf0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a563ad99-130d-4375-982c-f6e61cb995cf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_1a6cd6c1-b172-483b-88bd-8254208faf0f" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i47c3822dae37497995e92a9873e9050c_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_2ed2f702-2879-47fc-bdf0-0b71f8a237d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_2ed2f702-2879-47fc-bdf0-0b71f8a237d2" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_9646d015-6b10-45aa-93be-6727ecec6298" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_9646d015-6b10-45aa-93be-6727ecec6298" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_6722384c-1305-4cd1-8278-f0bec56753d8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_6722384c-1305-4cd1-8278-f0bec56753d8" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_dc98f860-b8b1-4f9f-a89e-c73adf7a724e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_dc98f860-b8b1-4f9f-a89e-c73adf7a724e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_d11f1929-a129-4689-a0ea-b9ecabbfdc12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_d11f1929-a129-4689-a0ea-b9ecabbfdc12" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_8fdd6564-be55-40c3-a2ae-097a80818e4d" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_cf996bfc-7caf-457b-ab7c-2e3209ebd09c" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_8fdd6564-be55-40c3-a2ae-097a80818e4d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_20b34dd1-524f-4e92-871a-e9bd15e0e94b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_8fdd6564-be55-40c3-a2ae-097a80818e4d" xlink:to="loc_srt_ProductOrServiceAxis_20b34dd1-524f-4e92-871a-e9bd15e0e94b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_20b34dd1-524f-4e92-871a-e9bd15e0e94b_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_20b34dd1-524f-4e92-871a-e9bd15e0e94b" xlink:to="loc_srt_ProductsAndServicesDomain_20b34dd1-524f-4e92-871a-e9bd15e0e94b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_fdfcf2c4-f2ea-4ee1-991c-834d951a20d9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_20b34dd1-524f-4e92-871a-e9bd15e0e94b" xlink:to="loc_srt_ProductsAndServicesDomain_fdfcf2c4-f2ea-4ee1-991c-834d951a20d9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_e3906730-b96d-419d-a357-fd407ca9d392" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_fdfcf2c4-f2ea-4ee1-991c-834d951a20d9" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_e3906730-b96d-419d-a357-fd407ca9d392" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_150158ee-6b29-4ab9-a9bf-7c09b37cd833" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_8fdd6564-be55-40c3-a2ae-097a80818e4d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_150158ee-6b29-4ab9-a9bf-7c09b37cd833" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_150158ee-6b29-4ab9-a9bf-7c09b37cd833_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_150158ee-6b29-4ab9-a9bf-7c09b37cd833" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_150158ee-6b29-4ab9-a9bf-7c09b37cd833_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_150158ee-6b29-4ab9-a9bf-7c09b37cd833" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_16a0d04f-7213-4f48-b019-52bc10bda4af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_16a0d04f-7213-4f48-b019-52bc10bda4af" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_14b1a5d7-aac8-42f2-a68c-80bde1cafdea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_14b1a5d7-aac8-42f2-a68c-80bde1cafdea" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_c7a5bcb7-1770-4991-a066-30f50a75a04e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_c7a5bcb7-1770-4991-a066-30f50a75a04e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_9cc0a63c-ffcc-448e-a284-d5ad70355fd2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_9cc0a63c-ffcc-448e-a284-d5ad70355fd2" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_16133368-f5a1-4092-bb0a-76667d808e11" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_16133368-f5a1-4092-bb0a-76667d808e11" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_c3ff845c-fcfd-44f4-af08-086ad0b60885" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_c3ff845c-fcfd-44f4-af08-086ad0b60885" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_1b4a603a-cf35-4a29-8f41-72c86bc92bc8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_1b4a603a-cf35-4a29-8f41-72c86bc92bc8" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_72c6f09f-9689-4c59-9dcb-5ca2fc817af7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_72c6f09f-9689-4c59-9dcb-5ca2fc817af7" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_983e8c96-cdde-4f2a-a4d5-89f762143c78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_983e8c96-cdde-4f2a-a4d5-89f762143c78" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_0299b36c-a7ce-4e5e-8863-b4ad2c31b495" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d06cab0c-a804-4a06-952f-0932613b72ac" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_0299b36c-a7ce-4e5e-8863-b4ad2c31b495" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_8fdd6564-be55-40c3-a2ae-097a80818e4d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c" xlink:to="loc_us-gaap_SegmentDomain_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ed3cd910-7420-4c58-9b0c-c7aff9801805" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f3a1bd82-d2ac-40b8-946d-9bdd6f3a6a4c" xlink:to="loc_us-gaap_SegmentDomain_ed3cd910-7420-4c58-9b0c-c7aff9801805" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_85388d4b-0e94-4428-8a7c-79e52c00f52c" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ed3cd910-7420-4c58-9b0c-c7aff9801805" xlink:to="loc_cna_SpecialtySegmentMember_85388d4b-0e94-4428-8a7c-79e52c00f52c" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="i01fcb46c04704484b66722cf92a8103a_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyMedicalProfessionalLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClaimsDevelopmentLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_2fe035bf-8de3-4d60-a5ab-89e93b6b34cb" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_2fe035bf-8de3-4d60-a5ab-89e93b6b34cb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_51be7d27-5fd5-4e37-8203-9c10e498dcef" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_51be7d27-5fd5-4e37-8203-9c10e498dcef" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_3e9f8d41-abb3-4149-b6b8-406ef4312588" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_3e9f8d41-abb3-4149-b6b8-406ef4312588" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability_7cf0912a-0675-481f-b139-f720b6cb30ef" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentMedicalProfessionalLiability_7cf0912a-0675-481f-b139-f720b6cb30ef" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_9813c48d-ae92-46c2-8d41-c1ab96abc28a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_0c592da5-79bd-40c6-aa3b-821b7a0bd03b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_9813c48d-ae92-46c2-8d41-c1ab96abc28a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_83b5a1cf-3558-4078-b681-83340d238d66" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_9813c48d-ae92-46c2-8d41-c1ab96abc28a" xlink:to="loc_srt_ProductOrServiceAxis_83b5a1cf-3558-4078-b681-83340d238d66" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_83b5a1cf-3558-4078-b681-83340d238d66_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_83b5a1cf-3558-4078-b681-83340d238d66" xlink:to="loc_srt_ProductsAndServicesDomain_83b5a1cf-3558-4078-b681-83340d238d66_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_92803a50-1065-4d45-a18d-ae4925df5fd0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_83b5a1cf-3558-4078-b681-83340d238d66" xlink:to="loc_srt_ProductsAndServicesDomain_92803a50-1065-4d45-a18d-ae4925df5fd0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_342d5dd5-0ac2-4c13-ba62-de5bdb52c513" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_92803a50-1065-4d45-a18d-ae4925df5fd0" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_342d5dd5-0ac2-4c13-ba62-de5bdb52c513" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_696c1167-e051-49ce-807c-3799ce320207" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_9813c48d-ae92-46c2-8d41-c1ab96abc28a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_696c1167-e051-49ce-807c-3799ce320207" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_696c1167-e051-49ce-807c-3799ce320207_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_696c1167-e051-49ce-807c-3799ce320207" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_696c1167-e051-49ce-807c-3799ce320207_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_696c1167-e051-49ce-807c-3799ce320207" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_4afec04c-96be-4c2d-93d5-c63ce539c234" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_4afec04c-96be-4c2d-93d5-c63ce539c234" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_8fd8ea91-73ca-42aa-9ff7-1b97ebe7cc70" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_8fd8ea91-73ca-42aa-9ff7-1b97ebe7cc70" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_94d2003c-53eb-49e6-babc-57fa83b7020e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_94d2003c-53eb-49e6-babc-57fa83b7020e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_c54fe9aa-30ee-4c48-896b-d4d05b8342ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_c54fe9aa-30ee-4c48-896b-d4d05b8342ec" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_84c16416-a761-490b-a2bc-6f1a08beb69d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_84c16416-a761-490b-a2bc-6f1a08beb69d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_cf4f52b4-4d3f-4da4-a005-43c415541ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_cf4f52b4-4d3f-4da4-a005-43c415541ff3" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_6568f772-b67f-47ef-ab54-0d4807527a4e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_6568f772-b67f-47ef-ab54-0d4807527a4e" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_11364675-df8f-4158-8e30-dc4813c1f830" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_11364675-df8f-4158-8e30-dc4813c1f830" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_713f2778-85ce-46b1-8f6d-dd1e9eb82406" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4211ff35-f413-4bc8-a270-b0da55bfbdc5" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_713f2778-85ce-46b1-8f6d-dd1e9eb82406" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7bf3e3b2-f27d-4212-a505-a81825e1ad66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_9813c48d-ae92-46c2-8d41-c1ab96abc28a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7bf3e3b2-f27d-4212-a505-a81825e1ad66" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7bf3e3b2-f27d-4212-a505-a81825e1ad66_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7bf3e3b2-f27d-4212-a505-a81825e1ad66" xlink:to="loc_us-gaap_SegmentDomain_7bf3e3b2-f27d-4212-a505-a81825e1ad66_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f6fb3919-5d84-40d3-a8fc-700061a3b837" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7bf3e3b2-f27d-4212-a505-a81825e1ad66" xlink:to="loc_us-gaap_SegmentDomain_f6fb3919-5d84-40d3-a8fc-700061a3b837" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_9de56b0b-dba3-4102-8f01-46cb28d171b6" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f6fb3919-5d84-40d3-a8fc-700061a3b837" xlink:to="loc_cna_SpecialtySegmentMember_9de56b0b-dba3-4102-8f01-46cb28d171b6" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="i46118eca45d4440b8ca5dfd534ed1e34_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_1ecf598a-f853-47c9-ab73-aaed2a1cfd37" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_7114c1db-9791-486a-a003-0f7862fd15e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_1ecf598a-f853-47c9-ab73-aaed2a1cfd37" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_7114c1db-9791-486a-a003-0f7862fd15e9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_90ef1c72-a75f-4c3c-ae0c-22388bd2fa1c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_1ecf598a-f853-47c9-ab73-aaed2a1cfd37" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_90ef1c72-a75f-4c3c-ae0c-22388bd2fa1c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_127cdac4-6e22-40c8-9a8c-ab7f5574406d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_1ecf598a-f853-47c9-ab73-aaed2a1cfd37" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_127cdac4-6e22-40c8-9a8c-ab7f5574406d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_48b2443f-6486-4b2e-ad32-7d751090ef1f" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_1ecf598a-f853-47c9-ab73-aaed2a1cfd37" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_48b2443f-6486-4b2e-ad32-7d751090ef1f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_b0292236-45b3-4c17-a900-fa882a395d04" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_48b2443f-6486-4b2e-ad32-7d751090ef1f" xlink:to="loc_srt_ProductOrServiceAxis_b0292236-45b3-4c17-a900-fa882a395d04" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b0292236-45b3-4c17-a900-fa882a395d04_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_b0292236-45b3-4c17-a900-fa882a395d04" xlink:to="loc_srt_ProductsAndServicesDomain_b0292236-45b3-4c17-a900-fa882a395d04_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_a90043ad-1e0b-4572-9eea-a098eacb09b0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_b0292236-45b3-4c17-a900-fa882a395d04" xlink:to="loc_srt_ProductsAndServicesDomain_a90043ad-1e0b-4572-9eea-a098eacb09b0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_92d44560-4c9c-4c39-a6b5-360aa8f892e0" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_a90043ad-1e0b-4572-9eea-a098eacb09b0" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_92d44560-4c9c-4c39-a6b5-360aa8f892e0" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_a9fff96e-a743-46a9-b85a-8ccdff01c708" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_48b2443f-6486-4b2e-ad32-7d751090ef1f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_a9fff96e-a743-46a9-b85a-8ccdff01c708" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a9fff96e-a743-46a9-b85a-8ccdff01c708_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_a9fff96e-a743-46a9-b85a-8ccdff01c708" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a9fff96e-a743-46a9-b85a-8ccdff01c708_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_a9fff96e-a743-46a9-b85a-8ccdff01c708" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_72ef29e8-0701-46dc-95a1-6130b559ded8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_72ef29e8-0701-46dc-95a1-6130b559ded8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d9bf3fc5-d051-4b02-8d2d-bf9861e655d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d9bf3fc5-d051-4b02-8d2d-bf9861e655d6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_314038b5-1f7a-46bf-b386-2597df6b219a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_314038b5-1f7a-46bf-b386-2597df6b219a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_d67ac2d1-ac2e-4442-b23a-6d338e03989b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_d67ac2d1-ac2e-4442-b23a-6d338e03989b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_fac9e1d2-fa0f-4191-b0b4-67136eb7b71d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_fac9e1d2-fa0f-4191-b0b4-67136eb7b71d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_eb8fa316-750f-427e-ba7b-5f5698f80e4a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_eb8fa316-750f-427e-ba7b-5f5698f80e4a" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_3411fec8-c463-414b-946f-aa0561286d2b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_3411fec8-c463-414b-946f-aa0561286d2b" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_5d23309e-ab53-4501-ba36-40daa8c49c29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_5d23309e-ab53-4501-ba36-40daa8c49c29" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_dc27cda3-80f0-43de-9b18-51e63ee5a242" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_dc27cda3-80f0-43de-9b18-51e63ee5a242" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_d34837f6-6f67-4384-8a33-3dc1a377a83e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2f3e798-b07a-418d-8969-dd4e9e7e26ab" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_d34837f6-6f67-4384-8a33-3dc1a377a83e" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_48b2443f-6486-4b2e-ad32-7d751090ef1f" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57" xlink:to="loc_us-gaap_SegmentDomain_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f3578b87-12a6-4b38-ab40-0f613373e23c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_33d2aa87-1e10-4eaf-a8d0-8f5ff82f6f57" xlink:to="loc_us-gaap_SegmentDomain_f3578b87-12a6-4b38-ab40-0f613373e23c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_dcb4468b-dfd8-48aa-a489-7c6517ece617" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_f3578b87-12a6-4b38-ab40-0f613373e23c" xlink:to="loc_cna_SpecialtySegmentMember_dcb4468b-dfd8-48aa-a489-7c6517ece617" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="iacb58a4c64854b89b8823a3932dcf763_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_0200f232-2661-4a24-be0d-f490a50d024c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_0200f232-2661-4a24-be0d-f490a50d024c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_cac5c0d8-13e7-4111-a8b8-47021c6cf351" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_cac5c0d8-13e7-4111-a8b8-47021c6cf351" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_5f1a53d2-adec-41a6-96bd-27f6a4ee3a69" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_5f1a53d2-adec-41a6-96bd-27f6a4ee3a69" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_c448f4fc-81e6-45f2-b01c-914a20bc2315" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_c448f4fc-81e6-45f2-b01c-914a20bc2315" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_e11aff8f-6ae6-4bdd-a758-26e643f96dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_e11aff8f-6ae6-4bdd-a758-26e643f96dd5" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_f6b530a0-8c55-43de-af63-20675e64b355" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_4e3655c8-9703-4aab-b72a-d2aa51802b4d" xlink:to="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_f6b530a0-8c55-43de-af63-20675e64b355" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_884463c1-3520-4be4-9f78-5f00ba059a69" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_f6b530a0-8c55-43de-af63-20675e64b355" xlink:to="loc_srt_ProductOrServiceAxis_884463c1-3520-4be4-9f78-5f00ba059a69" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_884463c1-3520-4be4-9f78-5f00ba059a69_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_884463c1-3520-4be4-9f78-5f00ba059a69" xlink:to="loc_srt_ProductsAndServicesDomain_884463c1-3520-4be4-9f78-5f00ba059a69_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_516550b3-5d86-44e6-a7cf-22306ec8ceee" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_884463c1-3520-4be4-9f78-5f00ba059a69" xlink:to="loc_srt_ProductsAndServicesDomain_516550b3-5d86-44e6-a7cf-22306ec8ceee" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_b5e76007-a248-4d26-b2f7-f733674e5f97" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_516550b3-5d86-44e6-a7cf-22306ec8ceee" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_b5e76007-a248-4d26-b2f7-f733674e5f97" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_c713defa-3e67-4e0b-b31a-1df69e85eabb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_f6b530a0-8c55-43de-af63-20675e64b355" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_c713defa-3e67-4e0b-b31a-1df69e85eabb" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c713defa-3e67-4e0b-b31a-1df69e85eabb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_c713defa-3e67-4e0b-b31a-1df69e85eabb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c713defa-3e67-4e0b-b31a-1df69e85eabb_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_c713defa-3e67-4e0b-b31a-1df69e85eabb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_78a8471c-9aa3-44b9-9496-a720f3cccbaf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_78a8471c-9aa3-44b9-9496-a720f3cccbaf" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_640f7339-16d0-40bb-be34-96f43a51adcc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_640f7339-16d0-40bb-be34-96f43a51adcc" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_b076d86f-58f8-4992-b34e-3e53bbac24ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_b076d86f-58f8-4992-b34e-3e53bbac24ab" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_42ec2619-f983-4d26-ab2d-52818d21f38c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_42ec2619-f983-4d26-ab2d-52818d21f38c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_258f0596-cd55-4202-8ff1-f5d9f006ed53" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_258f0596-cd55-4202-8ff1-f5d9f006ed53" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_8a3fdc15-6a0e-425c-8290-50e560ca79b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_8a3fdc15-6a0e-425c-8290-50e560ca79b4" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_52853649-a771-41f9-9a7b-29590ae13521" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_52853649-a771-41f9-9a7b-29590ae13521" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_34c246ed-2eda-48c9-805e-d44edaeb2891" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_34c246ed-2eda-48c9-805e-d44edaeb2891" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f9c41437-e1bd-4658-8bae-36becdef2ab8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f9c41437-e1bd-4658-8bae-36becdef2ab8" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_937f5e14-4d40-4ccc-8eb1-7e168762af0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8cb4749b-ebb2-4198-a707-8fa6c5505b4f" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_937f5e14-4d40-4ccc-8eb1-7e168762af0f" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_238e4c8b-1a4a-48b8-995c-34a5dc4545d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_f6b530a0-8c55-43de-af63-20675e64b355" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_238e4c8b-1a4a-48b8-995c-34a5dc4545d2" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_238e4c8b-1a4a-48b8-995c-34a5dc4545d2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_238e4c8b-1a4a-48b8-995c-34a5dc4545d2" xlink:to="loc_us-gaap_SegmentDomain_238e4c8b-1a4a-48b8-995c-34a5dc4545d2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d7807d74-3f63-471d-9665-1dcf669e24ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_238e4c8b-1a4a-48b8-995c-34a5dc4545d2" xlink:to="loc_us-gaap_SegmentDomain_d7807d74-3f63-471d-9665-1dcf669e24ef" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_27eb5283-c070-407e-be5f-1d47d55799bd" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_d7807d74-3f63-471d-9665-1dcf669e24ef" xlink:to="loc_cna_SpecialtySegmentMember_27eb5283-c070-407e-be5f-1d47d55799bd" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="ib1b2c07ceaa74c40ac7a4b9f0cd121a0_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtyOtherProfessionalLiabilityandManagementLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClaimsDevelopmentLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_7cee06e7-9313-4466-9a08-bde8b56059d7" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_7cee06e7-9313-4466-9a08-bde8b56059d7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_00981345-fe8f-4d5e-ad00-a5f68de39421" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_00981345-fe8f-4d5e-ad00-a5f68de39421" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_135d15f4-a221-44f8-9c8d-cd19c81ce098" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_135d15f4-a221-44f8-9c8d-cd19c81ce098" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability_efbe8376-51b6-4778-8025-f502d87aed3d" xlink:href="cna-20221231.xsd#cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:to="loc_cna_NetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentOtherProfessionalLiabilityandManagementLiability_efbe8376-51b6-4778-8025-f502d87aed3d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_d0d4049e-13fc-416c-8f14-3a1dc0619cd1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_a305a113-35b8-45f5-992e-209a40d14b64" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_d0d4049e-13fc-416c-8f14-3a1dc0619cd1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_b65ff482-e6c7-4907-9128-8312a503a3e6" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_d0d4049e-13fc-416c-8f14-3a1dc0619cd1" xlink:to="loc_srt_ProductOrServiceAxis_b65ff482-e6c7-4907-9128-8312a503a3e6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b65ff482-e6c7-4907-9128-8312a503a3e6_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_b65ff482-e6c7-4907-9128-8312a503a3e6" xlink:to="loc_srt_ProductsAndServicesDomain_b65ff482-e6c7-4907-9128-8312a503a3e6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_59417b08-7e29-4b1f-bf15-ff64633d582d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_b65ff482-e6c7-4907-9128-8312a503a3e6" xlink:to="loc_srt_ProductsAndServicesDomain_59417b08-7e29-4b1f-bf15-ff64633d582d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_2938eba1-f3fb-4cfe-bc06-8fde0fdc028d" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_59417b08-7e29-4b1f-bf15-ff64633d582d" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_2938eba1-f3fb-4cfe-bc06-8fde0fdc028d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_b312f463-a801-4561-9066-b82bae69486b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_d0d4049e-13fc-416c-8f14-3a1dc0619cd1" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_b312f463-a801-4561-9066-b82bae69486b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_b312f463-a801-4561-9066-b82bae69486b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_b312f463-a801-4561-9066-b82bae69486b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_b312f463-a801-4561-9066-b82bae69486b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_b312f463-a801-4561-9066-b82bae69486b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_c4ae43fe-c685-4593-9aaa-8c719e538326" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_c4ae43fe-c685-4593-9aaa-8c719e538326" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_f4136cd0-0f82-4f81-9c30-bcecaa054b54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_f4136cd0-0f82-4f81-9c30-bcecaa054b54" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_cfb1ac15-2096-4756-ae0f-17eb9ad249ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_cfb1ac15-2096-4756-ae0f-17eb9ad249ad" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_5e1c38ef-61fb-400a-aa6a-ab2838f58834" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_5e1c38ef-61fb-400a-aa6a-ab2838f58834" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_bb12a441-a032-4a76-9080-e6787973304b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_bb12a441-a032-4a76-9080-e6787973304b" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_ac9517f6-2a12-4e60-9dbe-ed994dc14b0d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_ac9517f6-2a12-4e60-9dbe-ed994dc14b0d" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_31dd3961-767d-4477-ae40-9474e3bcb0d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_31dd3961-767d-4477-ae40-9474e3bcb0d5" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_168fe644-c739-4d5e-93f1-b48919106f7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_168fe644-c739-4d5e-93f1-b48919106f7f" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_60ea5b1f-ad5c-4f9a-a0c7-23309201b809" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_4f10823f-4005-4521-842a-f8f30b6c1ff0" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_60ea5b1f-ad5c-4f9a-a0c7-23309201b809" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_2316f834-9572-47eb-9bd1-8e3844377f93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_d0d4049e-13fc-416c-8f14-3a1dc0619cd1" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_2316f834-9572-47eb-9bd1-8e3844377f93" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_2316f834-9572-47eb-9bd1-8e3844377f93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2316f834-9572-47eb-9bd1-8e3844377f93" xlink:to="loc_us-gaap_SegmentDomain_2316f834-9572-47eb-9bd1-8e3844377f93_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_b77c2697-de0b-44c6-8b30-21962685069c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_2316f834-9572-47eb-9bd1-8e3844377f93" xlink:to="loc_us-gaap_SegmentDomain_b77c2697-de0b-44c6-8b30-21962685069c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_9009e230-31eb-46f2-9b1a-5d7f3fbdce52" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_b77c2697-de0b-44c6-8b30-21962685069c" xlink:to="loc_cna_SpecialtySegmentMember_9009e230-31eb-46f2-9b1a-5d7f3fbdce52" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="ib51b04756fc1427db6f8d2ccd76aa431_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_7a9dccff-be71-4a5e-b64e-99d3e7265b04" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_23c63c61-2a65-43cd-953d-c95f9f9b57c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_7a9dccff-be71-4a5e-b64e-99d3e7265b04" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_23c63c61-2a65-43cd-953d-c95f9f9b57c9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_a1728cde-b7ce-4d2d-811c-c81921b0c9fd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_7a9dccff-be71-4a5e-b64e-99d3e7265b04" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_a1728cde-b7ce-4d2d-811c-c81921b0c9fd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_8b0d2366-b9f5-4787-b5f8-97ee75c20af3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_7a9dccff-be71-4a5e-b64e-99d3e7265b04" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_8b0d2366-b9f5-4787-b5f8-97ee75c20af3" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a83397fb-e5b6-4ead-9ec9-5296ec0230bb" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_7a9dccff-be71-4a5e-b64e-99d3e7265b04" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a83397fb-e5b6-4ead-9ec9-5296ec0230bb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_733dc7ef-5de3-4d44-b599-94fadd0ac526" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a83397fb-e5b6-4ead-9ec9-5296ec0230bb" xlink:to="loc_srt_ProductOrServiceAxis_733dc7ef-5de3-4d44-b599-94fadd0ac526" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_733dc7ef-5de3-4d44-b599-94fadd0ac526_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_733dc7ef-5de3-4d44-b599-94fadd0ac526" xlink:to="loc_srt_ProductsAndServicesDomain_733dc7ef-5de3-4d44-b599-94fadd0ac526_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7113e014-1b00-4ed5-8def-bb5170f52558" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_733dc7ef-5de3-4d44-b599-94fadd0ac526" xlink:to="loc_srt_ProductsAndServicesDomain_7113e014-1b00-4ed5-8def-bb5170f52558" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_d2ee5372-022c-4768-a58e-2e92eace6241" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7113e014-1b00-4ed5-8def-bb5170f52558" xlink:to="loc_cna_SuretyMember_d2ee5372-022c-4768-a58e-2e92eace6241" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_fc39db16-60c1-4a67-9e2c-bc8a3d879485" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a83397fb-e5b6-4ead-9ec9-5296ec0230bb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_fc39db16-60c1-4a67-9e2c-bc8a3d879485" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_fc39db16-60c1-4a67-9e2c-bc8a3d879485_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_fc39db16-60c1-4a67-9e2c-bc8a3d879485" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_fc39db16-60c1-4a67-9e2c-bc8a3d879485_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_fc39db16-60c1-4a67-9e2c-bc8a3d879485" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_d32429fc-fb2f-4473-8f76-efaaa8d15fce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_d32429fc-fb2f-4473-8f76-efaaa8d15fce" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_a0d7fa49-22b6-481d-9134-94503b29fde9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_a0d7fa49-22b6-481d-9134-94503b29fde9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_1a08e728-06b3-4904-b96a-f423a593f1fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_1a08e728-06b3-4904-b96a-f423a593f1fa" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e5d2e0c3-1da0-464c-b1d1-1804735d0d48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e5d2e0c3-1da0-464c-b1d1-1804735d0d48" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_54fad758-5fcb-4e8d-b456-500482eab631" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_54fad758-5fcb-4e8d-b456-500482eab631" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_f6f5e3b8-4881-4df4-bcd7-5a64c752da2b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_f6f5e3b8-4881-4df4-bcd7-5a64c752da2b" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_075e22d6-69ad-48d2-8c20-04fc2e508d87" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_075e22d6-69ad-48d2-8c20-04fc2e508d87" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_973b28dd-aa69-44fb-b987-c81a3debac1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_973b28dd-aa69-44fb-b987-c81a3debac1b" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_62703c6f-d818-4c3e-9804-31357b7eac24" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_62703c6f-d818-4c3e-9804-31357b7eac24" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_af3985f6-b0d0-4049-a796-72b7621a2f36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_567a7461-d355-471d-8301-ce225153b285" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_af3985f6-b0d0-4049-a796-72b7621a2f36" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ba4d539d-c862-466d-a700-f9967e8be6b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_a83397fb-e5b6-4ead-9ec9-5296ec0230bb" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ba4d539d-c862-466d-a700-f9967e8be6b4" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ba4d539d-c862-466d-a700-f9967e8be6b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ba4d539d-c862-466d-a700-f9967e8be6b4" xlink:to="loc_us-gaap_SegmentDomain_ba4d539d-c862-466d-a700-f9967e8be6b4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_2e68a0e2-2f20-4f60-ab9c-cc0125eafb6a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ba4d539d-c862-466d-a700-f9967e8be6b4" xlink:to="loc_us-gaap_SegmentDomain_2e68a0e2-2f20-4f60-ab9c-cc0125eafb6a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_1f028b25-efe1-4c91-b331-997f9d8faf77" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2e68a0e2-2f20-4f60-ab9c-cc0125eafb6a" xlink:to="loc_cna_SpecialtySegmentMember_1f028b25-efe1-4c91-b331-997f9d8faf77" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i3749a0d19fb9462489b7f04d4e4fdc8c_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c67b6dfc-4b6e-4fa8-b1ba-20679060a120" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c67b6dfc-4b6e-4fa8-b1ba-20679060a120" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_8313cb44-bef2-45c0-8522-b39dc6b491ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_8313cb44-bef2-45c0-8522-b39dc6b491ec" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_3558e617-3dde-4a3e-bdd2-8786b3b02ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_3558e617-3dde-4a3e-bdd2-8786b3b02ef0" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_61a5e7a8-f1a5-48b8-8496-a728f900f02d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_61a5e7a8-f1a5-48b8-8496-a728f900f02d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_3c45ed09-37d6-4958-915c-819fdf2dfe63" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_3c45ed09-37d6-4958-915c-819fdf2dfe63" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_fe00cde6-6a48-4e4d-8c84-64dbdc15608c" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_a32800ac-3e7f-466a-8470-70fb3a138b4e" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_fe00cde6-6a48-4e4d-8c84-64dbdc15608c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_951d22b0-9304-43b9-ba05-5ad203778377" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_fe00cde6-6a48-4e4d-8c84-64dbdc15608c" xlink:to="loc_srt_ProductOrServiceAxis_951d22b0-9304-43b9-ba05-5ad203778377" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_951d22b0-9304-43b9-ba05-5ad203778377_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_951d22b0-9304-43b9-ba05-5ad203778377" xlink:to="loc_srt_ProductsAndServicesDomain_951d22b0-9304-43b9-ba05-5ad203778377_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b3cb4d83-2415-4afb-9df8-bfb47a742c39" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_951d22b0-9304-43b9-ba05-5ad203778377" xlink:to="loc_srt_ProductsAndServicesDomain_b3cb4d83-2415-4afb-9df8-bfb47a742c39" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_2e697ddf-df75-4f54-931b-bc7aaede0783" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b3cb4d83-2415-4afb-9df8-bfb47a742c39" xlink:to="loc_cna_SuretyMember_2e697ddf-df75-4f54-931b-bc7aaede0783" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9a4c57e9-6303-4f74-8e71-c0aa66006c54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_fe00cde6-6a48-4e4d-8c84-64dbdc15608c" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9a4c57e9-6303-4f74-8e71-c0aa66006c54" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9a4c57e9-6303-4f74-8e71-c0aa66006c54_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9a4c57e9-6303-4f74-8e71-c0aa66006c54" xlink:to="loc_us-gaap_SegmentDomain_9a4c57e9-6303-4f74-8e71-c0aa66006c54_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_592d2508-b3d5-4e8f-ac71-88632487e389" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9a4c57e9-6303-4f74-8e71-c0aa66006c54" xlink:to="loc_us-gaap_SegmentDomain_592d2508-b3d5-4e8f-ac71-88632487e389" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_fcc3b8a8-169b-47e2-bea7-08d599592986" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_592d2508-b3d5-4e8f-ac71-88632487e389" xlink:to="loc_cna_SpecialtySegmentMember_fcc3b8a8-169b-47e2-bea7-08d599592986" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_46589865-f0d8-4655-8cf9-21e777064aa9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_fe00cde6-6a48-4e4d-8c84-64dbdc15608c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_46589865-f0d8-4655-8cf9-21e777064aa9" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_46589865-f0d8-4655-8cf9-21e777064aa9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_46589865-f0d8-4655-8cf9-21e777064aa9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_46589865-f0d8-4655-8cf9-21e777064aa9_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_46589865-f0d8-4655-8cf9-21e777064aa9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_27f20bdf-944e-4cef-a3c2-3050c11c8ce3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_27f20bdf-944e-4cef-a3c2-3050c11c8ce3" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_6102b5b4-989b-478c-b183-3fd47d1a5d3e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_6102b5b4-989b-478c-b183-3fd47d1a5d3e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_ff80dda9-3ddc-45a5-b16d-36e589a5174e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_ff80dda9-3ddc-45a5-b16d-36e589a5174e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_ff162bf9-2ae0-4253-b282-a30c2ea661ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_ff162bf9-2ae0-4253-b282-a30c2ea661ed" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_2ba5e0bb-f911-4bf4-8658-178ef37bef48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_2ba5e0bb-f911-4bf4-8658-178ef37bef48" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_2b06469e-2cb4-4be8-adde-4df00763cfad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_2b06469e-2cb4-4be8-adde-4df00763cfad" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_b332472d-8649-43e3-add6-b30a9bcae1d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_b332472d-8649-43e3-add6-b30a9bcae1d6" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_4efc57cf-fb15-4b3b-a7bf-86d2f59def5a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_4efc57cf-fb15-4b3b-a7bf-86d2f59def5a" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_53904a52-ea7a-47bb-8476-37c5f2b08f45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_53904a52-ea7a-47bb-8476-37c5f2b08f45" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_9b7e8429-91bb-4cad-9d6b-8b848992733f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e2a5548b-d238-4c9b-aebf-a4cc62cd2052" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_9b7e8429-91bb-4cad-9d6b-8b848992733f" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="i2efecb6bd02e4583a9f139496f65d94c_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesSpecialtySuretyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClaimsDevelopmentLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_e625f854-c8fd-4873-ac2b-4d5820710b4c" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_e625f854-c8fd-4873-ac2b-4d5820710b4c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_d5d70229-3c53-4918-83ae-a891de3c5261" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_d5d70229-3c53-4918-83ae-a891de3c5261" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_7993704a-7b9f-4ea7-a957-78e98e3c5d8b" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_7993704a-7b9f-4ea7-a957-78e98e3c5d8b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety_874ab5ea-46b2-4e75-ae65-c13c6d830c8e" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSurety_874ab5ea-46b2-4e75-ae65-c13c6d830c8e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_93f24711-8483-4735-8005-22b6c09f8f1e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems_e86e4097-1503-43c6-8a3b-cfda0ff7300b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_93f24711-8483-4735-8005-22b6c09f8f1e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_7c23ae54-6066-4826-a453-ab4d20df4c91" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_93f24711-8483-4735-8005-22b6c09f8f1e" xlink:to="loc_srt_ProductOrServiceAxis_7c23ae54-6066-4826-a453-ab4d20df4c91" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7c23ae54-6066-4826-a453-ab4d20df4c91_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_7c23ae54-6066-4826-a453-ab4d20df4c91" xlink:to="loc_srt_ProductsAndServicesDomain_7c23ae54-6066-4826-a453-ab4d20df4c91_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_20dc139e-9993-493e-bfc5-8d82e849171d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_7c23ae54-6066-4826-a453-ab4d20df4c91" xlink:to="loc_srt_ProductsAndServicesDomain_20dc139e-9993-493e-bfc5-8d82e849171d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_6dd6f4c7-c40c-4a56-b120-0cdd096e8c23" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_20dc139e-9993-493e-bfc5-8d82e849171d" xlink:to="loc_cna_SuretyMember_6dd6f4c7-c40c-4a56-b120-0cdd096e8c23" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_6844ad38-11f9-41ca-8ee8-43c15e806aff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_93f24711-8483-4735-8005-22b6c09f8f1e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_6844ad38-11f9-41ca-8ee8-43c15e806aff" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_6844ad38-11f9-41ca-8ee8-43c15e806aff_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_6844ad38-11f9-41ca-8ee8-43c15e806aff" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_6844ad38-11f9-41ca-8ee8-43c15e806aff_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_6844ad38-11f9-41ca-8ee8-43c15e806aff" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_f071636b-6ca0-49c5-8cc3-bcfffd2bea2b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_f071636b-6ca0-49c5-8cc3-bcfffd2bea2b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_84cc20c6-56d3-4ede-a18b-f832777b3968" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_84cc20c6-56d3-4ede-a18b-f832777b3968" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_8ba6850c-d127-4687-ad4d-4250c657ac50" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_8ba6850c-d127-4687-ad4d-4250c657ac50" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_85ed1895-14f6-438e-b77b-4623554b0cc6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_85ed1895-14f6-438e-b77b-4623554b0cc6" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_4576d7f0-94a8-4a48-9ec2-2c64e5f6dd67" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_4576d7f0-94a8-4a48-9ec2-2c64e5f6dd67" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_e333dabc-d07d-4173-b6cf-d83412389d1f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_e333dabc-d07d-4173-b6cf-d83412389d1f" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_9e7ab9cd-dea6-47b9-a87f-37d5961f26ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_9e7ab9cd-dea6-47b9-a87f-37d5961f26ba" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_fe64c2d4-a1eb-40d5-95cd-7cf62bbbf20f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_fe64c2d4-a1eb-40d5-95cd-7cf62bbbf20f" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_0686e460-dfc3-4842-9695-844044ffff91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c218dfc3-6d6a-45ab-a00f-9c0692f882e2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_0686e460-dfc3-4842-9695-844044ffff91" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_fb8d34dc-cff7-46dd-9419-c21bed3b5995" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsClaimsDevelopmentTable_93f24711-8483-4735-8005-22b6c09f8f1e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_fb8d34dc-cff7-46dd-9419-c21bed3b5995" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fb8d34dc-cff7-46dd-9419-c21bed3b5995_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fb8d34dc-cff7-46dd-9419-c21bed3b5995" xlink:to="loc_us-gaap_SegmentDomain_fb8d34dc-cff7-46dd-9419-c21bed3b5995_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_eb19ea8b-4d04-4517-9916-390502baa7de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_fb8d34dc-cff7-46dd-9419-c21bed3b5995" xlink:to="loc_us-gaap_SegmentDomain_eb19ea8b-4d04-4517-9916-390502baa7de" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_acbf3df0-31ba-4d7f-9617-95f29925824c" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_eb19ea8b-4d04-4517-9916-390502baa7de" xlink:to="loc_cna_SpecialtySegmentMember_acbf3df0-31ba-4d7f-9617-95f29925824c" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails" xlink:type="extended" id="ia6b33345bb474e3eafddbd1b87a7177b_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialNetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_c0ae5517-aa63-4ec9-a2cf-9b5fb4330c8f" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_c0ae5517-aa63-4ec9-a2cf-9b5fb4330c8f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability_7739b8e9-5be0-4e88-a3e9-be3385e0ae11" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability_7739b8e9-5be0-4e88-a3e9-be3385e0ae11" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation_44cdc844-f5b8-4026-94f2-7f2c1127ce5f" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation_44cdc844-f5b8-4026-94f2-7f2c1127ce5f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther_12d3bf3e-5a4c-4ffd-a374-56dcb3db8da0" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentPropertyAndOther_12d3bf3e-5a4c-4ffd-a374-56dcb3db8da0" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_05c97fb5-699f-4994-8cc4-2949249e69a2" xlink:href="cna-20221231.xsd#cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_05c97fb5-699f-4994-8cc4-2949249e69a2" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_41d99db0-8a1e-44e4-bffb-312e142ff401" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_1c11ac9b-9c51-4a57-b9b9-e6f9e67e4b29" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_41d99db0-8a1e-44e4-bffb-312e142ff401" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_a82c142d-15bb-42a7-9970-d139c2f47a68" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_41d99db0-8a1e-44e4-bffb-312e142ff401" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_a82c142d-15bb-42a7-9970-d139c2f47a68" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a82c142d-15bb-42a7-9970-d139c2f47a68_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a82c142d-15bb-42a7-9970-d139c2f47a68" xlink:to="loc_us-gaap_SegmentDomain_a82c142d-15bb-42a7-9970-d139c2f47a68_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_852ccbdb-447b-433f-95c9-2a46a3b19567" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a82c142d-15bb-42a7-9970-d139c2f47a68" xlink:to="loc_us-gaap_SegmentDomain_852ccbdb-447b-433f-95c9-2a46a3b19567" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_d61df05d-c3a3-44f2-9aa3-7134a3591163" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_852ccbdb-447b-433f-95c9-2a46a3b19567" xlink:to="loc_cna_CommercialSegmentMember_d61df05d-c3a3-44f2-9aa3-7134a3591163" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoShortDurationContractsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoShortDurationContractsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoShortDurationContractsDetails" xlink:type="extended" id="i446ec35ece4849ddaaf2aee5c865d798_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoShortDurationContractsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_dc8debba-f4db-4596-8c9f-3dc709b29aa6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_c01c86c5-d70e-44d5-91d1-7df6b7ebb7df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_dc8debba-f4db-4596-8c9f-3dc709b29aa6" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_c01c86c5-d70e-44d5-91d1-7df6b7ebb7df" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_a185a0ad-b5c3-4140-aa2c-e7a2c6e347d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_dc8debba-f4db-4596-8c9f-3dc709b29aa6" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_a185a0ad-b5c3-4140-aa2c-e7a2c6e347d9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_a185a0ad-b5c3-4140-aa2c-e7a2c6e347d9" xlink:to="loc_srt_ProductOrServiceAxis_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7" xlink:to="loc_srt_ProductsAndServicesDomain_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_c8f136e0-7c2b-486d-bdc9-7b8f5c7396c7" xlink:to="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_4c6ce2d1-864a-43bd-bc9b-58e83dac2cd9" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:to="loc_cna_CommercialAutoProductLineMember_4c6ce2d1-864a-43bd-bc9b-58e83dac2cd9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_1e7e6db9-c8f8-462c-87e2-91c3ae2c1610" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:to="loc_us-gaap_GeneralLiabilityMember_1e7e6db9-c8f8-462c-87e2-91c3ae2c1610" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_e526f2e6-a583-4dff-ade9-cbe56758a96f" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:to="loc_cna_WorkersCompensationMember_e526f2e6-a583-4dff-ade9-cbe56758a96f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PropertyandOtherMember_9571b389-08b1-4574-82be-bdd6e2d2b55f" xlink:href="cna-20221231.xsd#cna_PropertyandOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_696d3777-ff05-4da6-b7d2-91eee0ab22c5" xlink:to="loc_cna_PropertyandOtherMember_9571b389-08b1-4574-82be-bdd6e2d2b55f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_0202a254-6c21-471b-8613-ee10647fd877" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_a185a0ad-b5c3-4140-aa2c-e7a2c6e347d9" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_0202a254-6c21-471b-8613-ee10647fd877" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0202a254-6c21-471b-8613-ee10647fd877_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0202a254-6c21-471b-8613-ee10647fd877" xlink:to="loc_us-gaap_SegmentDomain_0202a254-6c21-471b-8613-ee10647fd877_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_51e57c5d-b101-4b10-94ad-9e7d3c7008ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_0202a254-6c21-471b-8613-ee10647fd877" xlink:to="loc_us-gaap_SegmentDomain_51e57c5d-b101-4b10-94ad-9e7d3c7008ab" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_61b86afb-e04e-4e99-87ad-3fd4c0f3ba70" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_51e57c5d-b101-4b10-94ad-9e7d3c7008ab" xlink:to="loc_cna_CommercialSegmentMember_61b86afb-e04e-4e99-87ad-3fd4c0f3ba70" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="iea7852a66e2e4836beeba02f8311db60_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_8ca6bb9e-810c-43ce-9a86-6c8771945c77" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_6e2da21a-86c0-40d1-82a9-a4649132c41a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_8ca6bb9e-810c-43ce-9a86-6c8771945c77" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_6e2da21a-86c0-40d1-82a9-a4649132c41a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_7fb68072-7472-46d9-80e9-69b4ecc3fd41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_8ca6bb9e-810c-43ce-9a86-6c8771945c77" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_7fb68072-7472-46d9-80e9-69b4ecc3fd41" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_78a655a7-1207-42f5-843d-598875211036" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_8ca6bb9e-810c-43ce-9a86-6c8771945c77" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_78a655a7-1207-42f5-843d-598875211036" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_bc648db3-b1b1-483e-ae5c-21cadd4b4fcf" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_8ca6bb9e-810c-43ce-9a86-6c8771945c77" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_bc648db3-b1b1-483e-ae5c-21cadd4b4fcf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_5c4aaa12-7222-4555-8511-868c26545bbb" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_bc648db3-b1b1-483e-ae5c-21cadd4b4fcf" xlink:to="loc_srt_ProductOrServiceAxis_5c4aaa12-7222-4555-8511-868c26545bbb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5c4aaa12-7222-4555-8511-868c26545bbb_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_5c4aaa12-7222-4555-8511-868c26545bbb" xlink:to="loc_srt_ProductsAndServicesDomain_5c4aaa12-7222-4555-8511-868c26545bbb_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7a1433e3-2569-483a-ace7-26904e0a1868" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_5c4aaa12-7222-4555-8511-868c26545bbb" xlink:to="loc_srt_ProductsAndServicesDomain_7a1433e3-2569-483a-ace7-26904e0a1868" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_f9da1c80-583b-4afb-a75a-13f251518b6c" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7a1433e3-2569-483a-ace7-26904e0a1868" xlink:to="loc_cna_CommercialAutoProductLineMember_f9da1c80-583b-4afb-a75a-13f251518b6c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_bf28b798-1001-4a8b-af9b-d07963d23fc5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_bc648db3-b1b1-483e-ae5c-21cadd4b4fcf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_bf28b798-1001-4a8b-af9b-d07963d23fc5" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_bf28b798-1001-4a8b-af9b-d07963d23fc5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_bf28b798-1001-4a8b-af9b-d07963d23fc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_bf28b798-1001-4a8b-af9b-d07963d23fc5_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_bf28b798-1001-4a8b-af9b-d07963d23fc5" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a9eabd60-2c67-49cd-8375-0ae39a4802a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a9eabd60-2c67-49cd-8375-0ae39a4802a9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d4f34255-e08a-48b0-b3bf-68ec0abaffe9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d4f34255-e08a-48b0-b3bf-68ec0abaffe9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_ef54ce49-33f4-4dc6-8e32-640f01c9c54d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_ef54ce49-33f4-4dc6-8e32-640f01c9c54d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_a5b13402-2a50-4618-b568-df428a160056" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_a5b13402-2a50-4618-b568-df428a160056" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_841be6f1-8e61-4842-803a-2655a0326f6e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_841be6f1-8e61-4842-803a-2655a0326f6e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_e37004e4-614e-48cf-9d44-d358b6e8d485" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_e37004e4-614e-48cf-9d44-d358b6e8d485" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_6bc43d62-b967-4a90-92f1-f7ae0a502825" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_6bc43d62-b967-4a90-92f1-f7ae0a502825" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_6d98fb49-7c5f-4ae2-9aca-2e60904c1540" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_6d98fb49-7c5f-4ae2-9aca-2e60904c1540" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_459f514d-6447-4f15-94c0-11b25e2a8d48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_459f514d-6447-4f15-94c0-11b25e2a8d48" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_6d000eab-ad7f-4815-b67d-247813869785" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_de396107-b5ee-42f0-b704-8b6c73cf1afb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_6d000eab-ad7f-4815-b67d-247813869785" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_bc648db3-b1b1-483e-ae5c-21cadd4b4fcf" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5" xlink:to="loc_us-gaap_SegmentDomain_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_aca3776d-5d8b-4c78-bcdc-a9b089aac639" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_8d1bb62b-e61f-4c2b-aace-4040fc69ccd5" xlink:to="loc_us-gaap_SegmentDomain_aca3776d-5d8b-4c78-bcdc-a9b089aac639" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_5db76b8b-2560-4779-ac60-1508f522a7d7" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_aca3776d-5d8b-4c78-bcdc-a9b089aac639" xlink:to="loc_cna_CommercialSegmentMember_5db76b8b-2560-4779-ac60-1508f522a7d7" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i670e1fccf37f4937a46035106fc84c91_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c30040ab-12a7-4e0e-b67b-6a279e8b1886" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c30040ab-12a7-4e0e-b67b-6a279e8b1886" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_62f4bb28-b21b-405b-b4ca-0e51396f52ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_62f4bb28-b21b-405b-b4ca-0e51396f52ac" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_c6541d6e-f3d6-446f-9daf-77f9c6d5bdad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_c6541d6e-f3d6-446f-9daf-77f9c6d5bdad" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_b46f7302-8f56-4830-8c57-ac9efd42929d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_b46f7302-8f56-4830-8c57-ac9efd42929d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_f5cce5f8-ee36-422c-9d48-45d817834ebe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_f5cce5f8-ee36-422c-9d48-45d817834ebe" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_e227e71f-bc45-445f-bbda-0c629175c16e" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_4cbf4f68-b883-4921-96ff-80ae3b5f8066" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_e227e71f-bc45-445f-bbda-0c629175c16e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_b5c5426f-542c-402f-ac47-015e70e5bd6e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_e227e71f-bc45-445f-bbda-0c629175c16e" xlink:to="loc_srt_ProductOrServiceAxis_b5c5426f-542c-402f-ac47-015e70e5bd6e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b5c5426f-542c-402f-ac47-015e70e5bd6e_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_b5c5426f-542c-402f-ac47-015e70e5bd6e" xlink:to="loc_srt_ProductsAndServicesDomain_b5c5426f-542c-402f-ac47-015e70e5bd6e_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c7fec22f-6a45-4ef9-ba19-72734db13d90" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_b5c5426f-542c-402f-ac47-015e70e5bd6e" xlink:to="loc_srt_ProductsAndServicesDomain_c7fec22f-6a45-4ef9-ba19-72734db13d90" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_beb9d65a-9ffc-486f-ba79-3ceb0e61b18a" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c7fec22f-6a45-4ef9-ba19-72734db13d90" xlink:to="loc_cna_CommercialAutoProductLineMember_beb9d65a-9ffc-486f-ba79-3ceb0e61b18a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c16d81a1-9be2-4c61-a441-f3b6e34d8fec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_e227e71f-bc45-445f-bbda-0c629175c16e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c16d81a1-9be2-4c61-a441-f3b6e34d8fec" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c16d81a1-9be2-4c61-a441-f3b6e34d8fec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c16d81a1-9be2-4c61-a441-f3b6e34d8fec" xlink:to="loc_us-gaap_SegmentDomain_c16d81a1-9be2-4c61-a441-f3b6e34d8fec_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fea7e97d-9c72-49f4-ba87-d70380d226ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c16d81a1-9be2-4c61-a441-f3b6e34d8fec" xlink:to="loc_us-gaap_SegmentDomain_fea7e97d-9c72-49f4-ba87-d70380d226ae" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_38726188-3660-4f32-9c9c-c434a3591ccb" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_fea7e97d-9c72-49f4-ba87-d70380d226ae" xlink:to="loc_cna_CommercialSegmentMember_38726188-3660-4f32-9c9c-c434a3591ccb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_e227e71f-bc45-445f-bbda-0c629175c16e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_445f396c-0c59-4b1b-9c0d-b083ec5ce2fb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_3aa1e602-d093-40b6-b177-14a0f35f7a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_3aa1e602-d093-40b6-b177-14a0f35f7a1a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_4b25422f-29eb-4659-934f-48a24b758cfc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_4b25422f-29eb-4659-934f-48a24b758cfc" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_94da7fc6-1b8a-48ce-932f-517cbf763dee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_94da7fc6-1b8a-48ce-932f-517cbf763dee" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_5d905198-0484-4584-8d03-3829ed696f49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_5d905198-0484-4584-8d03-3829ed696f49" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_37b1073c-317d-4a8a-81f8-7b221ef9e90e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_37b1073c-317d-4a8a-81f8-7b221ef9e90e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_468db23f-e2f1-47ca-b0fb-72e82147bb9a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_468db23f-e2f1-47ca-b0fb-72e82147bb9a" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_24fdc867-1ed2-414a-8c24-45a036f655e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_24fdc867-1ed2-414a-8c24-45a036f655e3" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_fbf1cdc2-1c56-4922-9cdb-5cfe26ad9813" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_fbf1cdc2-1c56-4922-9cdb-5cfe26ad9813" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_c59c61b4-1e1a-411e-8164-e94b25c87611" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_c59c61b4-1e1a-411e-8164-e94b25c87611" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_6a031390-1572-46a2-94d3-89d8caa75df1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_c11f6b19-bf72-4cce-aa6e-7f01497c80bb" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_6a031390-1572-46a2-94d3-89d8caa75df1" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="i09895943df994c04861059f0c0a0a857_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialCommercialAutoNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_4ca7190d-ee61-421e-adb9-efb9080c1a88" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_4ca7190d-ee61-421e-adb9-efb9080c1a88" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_2f81cc4e-2834-4639-b056-e83b7630bc36" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_2f81cc4e-2834-4639-b056-e83b7630bc36" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_799eba46-37bc-4a33-8cef-54f95dfe5ba3" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_799eba46-37bc-4a33-8cef-54f95dfe5ba3" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_182f5527-8273-407d-b37a-ba349fa0cf8a" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_182f5527-8273-407d-b37a-ba349fa0cf8a" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_6116cee4-4c34-4ce9-aa2c-2fc3e62deec0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_0ec386d7-229c-4686-b94a-1ecb6b5a2364" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_6116cee4-4c34-4ce9-aa2c-2fc3e62deec0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_db1fb4bc-9a6a-4459-ad92-756443719497" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_6116cee4-4c34-4ce9-aa2c-2fc3e62deec0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_db1fb4bc-9a6a-4459-ad92-756443719497" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_db1fb4bc-9a6a-4459-ad92-756443719497_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_db1fb4bc-9a6a-4459-ad92-756443719497" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_db1fb4bc-9a6a-4459-ad92-756443719497_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_db1fb4bc-9a6a-4459-ad92-756443719497" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a312abb2-b416-4f61-bcb0-a7d777300c1e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a312abb2-b416-4f61-bcb0-a7d777300c1e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_87fe5677-62e2-42d6-a236-bcea44298737" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_87fe5677-62e2-42d6-a236-bcea44298737" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_9c45a604-1bfe-4734-8161-918ca1dbff80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_9c45a604-1bfe-4734-8161-918ca1dbff80" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_dba23fb9-92f0-42d1-b360-ade34ec8668c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_dba23fb9-92f0-42d1-b360-ade34ec8668c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_df5ce47c-b976-4d1b-b008-a9159941fc47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_df5ce47c-b976-4d1b-b008-a9159941fc47" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_1a31b6f6-a8e8-4471-bb95-b345631376f8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_1a31b6f6-a8e8-4471-bb95-b345631376f8" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_44fe6cf9-352e-466e-833a-c27795cbae8b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_44fe6cf9-352e-466e-833a-c27795cbae8b" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a0176070-ee3f-43cc-81b2-2bb1e8282d90" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a0176070-ee3f-43cc-81b2-2bb1e8282d90" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_26461f31-bb76-44f3-aa25-e7c16d995813" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_83627709-8af5-42ab-a6ad-70b9ec699f4a" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_26461f31-bb76-44f3-aa25-e7c16d995813" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ea116fa0-4568-4e3b-8459-549dcb254082" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_6116cee4-4c34-4ce9-aa2c-2fc3e62deec0" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ea116fa0-4568-4e3b-8459-549dcb254082" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ea116fa0-4568-4e3b-8459-549dcb254082_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ea116fa0-4568-4e3b-8459-549dcb254082" xlink:to="loc_us-gaap_SegmentDomain_ea116fa0-4568-4e3b-8459-549dcb254082_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_09918265-07fc-4b5b-ad27-7e0d349211a1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ea116fa0-4568-4e3b-8459-549dcb254082" xlink:to="loc_us-gaap_SegmentDomain_09918265-07fc-4b5b-ad27-7e0d349211a1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_6c1b8507-7c97-47f7-839a-4c567e6d66e9" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_09918265-07fc-4b5b-ad27-7e0d349211a1" xlink:to="loc_cna_CommercialSegmentMember_6c1b8507-7c97-47f7-839a-4c567e6d66e9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_edc6490b-b995-491c-ba20-5b2378e474ae" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_6116cee4-4c34-4ce9-aa2c-2fc3e62deec0" xlink:to="loc_srt_ProductOrServiceAxis_edc6490b-b995-491c-ba20-5b2378e474ae" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_edc6490b-b995-491c-ba20-5b2378e474ae_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_edc6490b-b995-491c-ba20-5b2378e474ae" xlink:to="loc_srt_ProductsAndServicesDomain_edc6490b-b995-491c-ba20-5b2378e474ae_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_df708c1f-a6fc-4c9d-9fe1-ea4492fb29b5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_edc6490b-b995-491c-ba20-5b2378e474ae" xlink:to="loc_srt_ProductsAndServicesDomain_df708c1f-a6fc-4c9d-9fe1-ea4492fb29b5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_7e16a65a-d83d-4bd9-948d-e381418ec328" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_df708c1f-a6fc-4c9d-9fe1-ea4492fb29b5" xlink:to="loc_cna_CommercialAutoProductLineMember_7e16a65a-d83d-4bd9-948d-e381418ec328" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="ib8a2dd893bce4f968cb8f9873fc59616_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_19a93dd2-a316-4cb1-ac08-93ed83867475" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_30f9764c-f108-4671-9e7a-824c421c5d15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_19a93dd2-a316-4cb1-ac08-93ed83867475" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_30f9764c-f108-4671-9e7a-824c421c5d15" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_3fc8c82f-114a-4262-9cd4-becae34ba3ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_19a93dd2-a316-4cb1-ac08-93ed83867475" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_3fc8c82f-114a-4262-9cd4-becae34ba3ef" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_a960c721-dd0a-40d7-ba36-dd5cd08aa695" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_19a93dd2-a316-4cb1-ac08-93ed83867475" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_a960c721-dd0a-40d7-ba36-dd5cd08aa695" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3fb2229d-80ca-4ad6-b4cf-25e1f56500e1" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_19a93dd2-a316-4cb1-ac08-93ed83867475" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3fb2229d-80ca-4ad6-b4cf-25e1f56500e1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_f0c7ed02-3000-4cd6-8a11-21afb93f1301" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3fb2229d-80ca-4ad6-b4cf-25e1f56500e1" xlink:to="loc_srt_ProductOrServiceAxis_f0c7ed02-3000-4cd6-8a11-21afb93f1301" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f0c7ed02-3000-4cd6-8a11-21afb93f1301_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_f0c7ed02-3000-4cd6-8a11-21afb93f1301" xlink:to="loc_srt_ProductsAndServicesDomain_f0c7ed02-3000-4cd6-8a11-21afb93f1301_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_35e02238-de16-48c5-b4a4-d9a271558ae5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_f0c7ed02-3000-4cd6-8a11-21afb93f1301" xlink:to="loc_srt_ProductsAndServicesDomain_35e02238-de16-48c5-b4a4-d9a271558ae5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_a21042e6-a257-4a69-93b2-0f0fa1b50694" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_35e02238-de16-48c5-b4a4-d9a271558ae5" xlink:to="loc_us-gaap_GeneralLiabilityMember_a21042e6-a257-4a69-93b2-0f0fa1b50694" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_89f6bc0b-3ddd-4860-850a-b72443f21265" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3fb2229d-80ca-4ad6-b4cf-25e1f56500e1" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_89f6bc0b-3ddd-4860-850a-b72443f21265" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_89f6bc0b-3ddd-4860-850a-b72443f21265_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_89f6bc0b-3ddd-4860-850a-b72443f21265" xlink:to="loc_us-gaap_SegmentDomain_89f6bc0b-3ddd-4860-850a-b72443f21265_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a11a8f1f-d188-4f30-9a35-e595d1bd47d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_89f6bc0b-3ddd-4860-850a-b72443f21265" xlink:to="loc_us-gaap_SegmentDomain_a11a8f1f-d188-4f30-9a35-e595d1bd47d4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_cf00c493-f4df-4672-a909-3ee4d0e9e351" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a11a8f1f-d188-4f30-9a35-e595d1bd47d4" xlink:to="loc_cna_CommercialSegmentMember_cf00c493-f4df-4672-a909-3ee4d0e9e351" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_692f9db0-7160-4863-9403-31fb1ff9edf3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3fb2229d-80ca-4ad6-b4cf-25e1f56500e1" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_692f9db0-7160-4863-9403-31fb1ff9edf3" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_692f9db0-7160-4863-9403-31fb1ff9edf3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_692f9db0-7160-4863-9403-31fb1ff9edf3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_692f9db0-7160-4863-9403-31fb1ff9edf3_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_692f9db0-7160-4863-9403-31fb1ff9edf3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_64293b59-06de-4cd7-91eb-2a959723634a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_64293b59-06de-4cd7-91eb-2a959723634a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_fb3bf11d-29d8-42ed-9145-4d962432635f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_fb3bf11d-29d8-42ed-9145-4d962432635f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d55b1294-f5fe-42f0-84cf-8e760c6548d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d55b1294-f5fe-42f0-84cf-8e760c6548d6" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_7f0cab85-21dc-4615-818d-a331d9a8330b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_7f0cab85-21dc-4615-818d-a331d9a8330b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_66231d3a-f188-4c90-96f7-be3df8d3e02e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_66231d3a-f188-4c90-96f7-be3df8d3e02e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_fd635b46-e4f3-43f2-9110-a01787df9c86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_fd635b46-e4f3-43f2-9110-a01787df9c86" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_0d75b778-a45f-4daf-ad06-0ed993a1281f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_0d75b778-a45f-4daf-ad06-0ed993a1281f" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_7b00380b-c6cc-4187-b4cc-650ce2c33497" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_7b00380b-c6cc-4187-b4cc-650ce2c33497" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_7f698910-9d69-4c60-9b45-ee2dfdff9919" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_7f698910-9d69-4c60-9b45-ee2dfdff9919" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_864837b0-5314-4e37-92ef-4bdf24e15385" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e687a9a7-398b-4d97-97ba-2cb8b51e4341" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_864837b0-5314-4e37-92ef-4bdf24e15385" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i0019c3fcb7f94c90a5a3e0c9f0a117de_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_8ace4373-a59b-475d-b9ba-a61e5ccb08a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_8ace4373-a59b-475d-b9ba-a61e5ccb08a6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_388ce7d9-40fa-4056-b2a6-1bd71353952b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_388ce7d9-40fa-4056-b2a6-1bd71353952b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_a7eace60-fe66-4f1d-8cdd-8d7bc54f6c3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_a7eace60-fe66-4f1d-8cdd-8d7bc54f6c3b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_113cf665-4e4a-4c15-b992-58272df44704" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_113cf665-4e4a-4c15-b992-58272df44704" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_fba3ff38-d6f0-47bb-8163-f1cd14ba41c6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_fba3ff38-d6f0-47bb-8163-f1cd14ba41c6" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_c15bfc7e-2f78-4b45-b992-5aa38d46ee68" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_d3d713b3-69f4-47ae-93fa-f7960f18e282" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_c15bfc7e-2f78-4b45-b992-5aa38d46ee68" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_212bbe4e-9764-4765-847a-5210d314f54b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_c15bfc7e-2f78-4b45-b992-5aa38d46ee68" xlink:to="loc_srt_ProductOrServiceAxis_212bbe4e-9764-4765-847a-5210d314f54b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_212bbe4e-9764-4765-847a-5210d314f54b_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_212bbe4e-9764-4765-847a-5210d314f54b" xlink:to="loc_srt_ProductsAndServicesDomain_212bbe4e-9764-4765-847a-5210d314f54b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_6a951ee8-6dc3-4943-9638-1b95f0520656" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_212bbe4e-9764-4765-847a-5210d314f54b" xlink:to="loc_srt_ProductsAndServicesDomain_6a951ee8-6dc3-4943-9638-1b95f0520656" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_e5172aa8-bcfd-430e-87eb-2ffdff520c88" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_6a951ee8-6dc3-4943-9638-1b95f0520656" xlink:to="loc_us-gaap_GeneralLiabilityMember_e5172aa8-bcfd-430e-87eb-2ffdff520c88" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_c15bfc7e-2f78-4b45-b992-5aa38d46ee68" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6" xlink:to="loc_us-gaap_SegmentDomain_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3ea6014c-b0b2-43a3-83e5-a24ef925355b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_65480d37-bb1e-4f00-b6d9-ae39ebcb45e6" xlink:to="loc_us-gaap_SegmentDomain_3ea6014c-b0b2-43a3-83e5-a24ef925355b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_59b8f16c-f68d-44c5-826e-7ec08e388f5e" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_3ea6014c-b0b2-43a3-83e5-a24ef925355b" xlink:to="loc_cna_CommercialSegmentMember_59b8f16c-f68d-44c5-826e-7ec08e388f5e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_909c4d71-83c7-438e-80fa-fac1d5d59c58" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_c15bfc7e-2f78-4b45-b992-5aa38d46ee68" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_909c4d71-83c7-438e-80fa-fac1d5d59c58" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_909c4d71-83c7-438e-80fa-fac1d5d59c58_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_909c4d71-83c7-438e-80fa-fac1d5d59c58" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_909c4d71-83c7-438e-80fa-fac1d5d59c58_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_909c4d71-83c7-438e-80fa-fac1d5d59c58" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_79d6aa43-85d5-419f-a12d-6e6b471ad9e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_79d6aa43-85d5-419f-a12d-6e6b471ad9e8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d9e3749c-0d20-428b-8b38-aa06e4a11e94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d9e3749c-0d20-428b-8b38-aa06e4a11e94" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_6e493ffa-b5de-40e5-8de2-e2c40071e335" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_6e493ffa-b5de-40e5-8de2-e2c40071e335" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_92cf072f-e20d-464c-9d45-fad41f58ead2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_92cf072f-e20d-464c-9d45-fad41f58ead2" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_f6f83a40-1f41-4a66-95b9-b70c27eaf26d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_f6f83a40-1f41-4a66-95b9-b70c27eaf26d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_1b391ab4-2f37-44c9-b2f8-3d43771aed37" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_1b391ab4-2f37-44c9-b2f8-3d43771aed37" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_143a8cc4-d351-48d4-bc2e-128110f1dd30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_143a8cc4-d351-48d4-bc2e-128110f1dd30" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_60f8c81a-8b52-4ea3-8292-672efd048ea7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_60f8c81a-8b52-4ea3-8292-672efd048ea7" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_9718fd1f-4601-42a0-87c9-8e09ceab1688" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_9718fd1f-4601-42a0-87c9-8e09ceab1688" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_1da8d2a6-0a16-4ba0-90c3-9c4487d2b56e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2aed8515-bb9e-4ebf-8d9d-74501a9dfc52" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_1da8d2a6-0a16-4ba0-90c3-9c4487d2b56e" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="i99618025b30f4634b4bb1f8059066684_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialGeneralLiabilityNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_00dbf482-9694-4062-aa51-dc993c1ea5ca" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_00dbf482-9694-4062-aa51-dc993c1ea5ca" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_6ce5b089-345d-433e-a155-16120b6a4f39" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_6ce5b089-345d-433e-a155-16120b6a4f39" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_71d031dd-e432-42c7-8180-8888e643b239" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_71d031dd-e432-42c7-8180-8888e643b239" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability_ecb17083-60eb-49be-b407-27dbf8139a16" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentGeneralLiability_ecb17083-60eb-49be-b407-27dbf8139a16" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_06bf5e3b-afa6-40bf-a02d-0f724c739b00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_ac7df908-e4e4-484e-9287-b6369e31c78f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_06bf5e3b-afa6-40bf-a02d-0f724c739b00" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_f7b339cb-7c9f-4526-9b6c-d34122cfb28c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_06bf5e3b-afa6-40bf-a02d-0f724c739b00" xlink:to="loc_srt_ProductOrServiceAxis_f7b339cb-7c9f-4526-9b6c-d34122cfb28c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f7b339cb-7c9f-4526-9b6c-d34122cfb28c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_f7b339cb-7c9f-4526-9b6c-d34122cfb28c" xlink:to="loc_srt_ProductsAndServicesDomain_f7b339cb-7c9f-4526-9b6c-d34122cfb28c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_172f6ce4-2a4f-4870-844a-13638b517eea" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_f7b339cb-7c9f-4526-9b6c-d34122cfb28c" xlink:to="loc_srt_ProductsAndServicesDomain_172f6ce4-2a4f-4870-844a-13638b517eea" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_ddcbb725-4b6e-497a-8766-ac93acdb2861" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_172f6ce4-2a4f-4870-844a-13638b517eea" xlink:to="loc_us-gaap_GeneralLiabilityMember_ddcbb725-4b6e-497a-8766-ac93acdb2861" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_5ef032f7-511d-488f-8b6a-9ca1322facd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_06bf5e3b-afa6-40bf-a02d-0f724c739b00" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_5ef032f7-511d-488f-8b6a-9ca1322facd7" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5ef032f7-511d-488f-8b6a-9ca1322facd7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_5ef032f7-511d-488f-8b6a-9ca1322facd7" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5ef032f7-511d-488f-8b6a-9ca1322facd7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_5ef032f7-511d-488f-8b6a-9ca1322facd7" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_6b3ee329-28ef-4eb4-8c4f-341155439914" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_6b3ee329-28ef-4eb4-8c4f-341155439914" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d55977cd-ed41-410b-ad2f-d8c8e24924af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_d55977cd-ed41-410b-ad2f-d8c8e24924af" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d9f50b02-7daa-44ac-bce9-35f9449ffd15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d9f50b02-7daa-44ac-bce9-35f9449ffd15" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_1e583f86-c239-4468-b45d-e06124609a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_1e583f86-c239-4468-b45d-e06124609a8e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_68dfed03-5935-4b09-9c15-be42bc790d8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_68dfed03-5935-4b09-9c15-be42bc790d8c" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_33c841fe-7eb8-4630-8339-d993d8930562" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_33c841fe-7eb8-4630-8339-d993d8930562" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_f2567f43-267a-4565-9cc1-f7444d645b78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_f2567f43-267a-4565-9cc1-f7444d645b78" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_c70e047c-5aba-4192-a388-b27e213189f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_c70e047c-5aba-4192-a388-b27e213189f7" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f865e48a-fb10-4533-a2ac-397775ac4b48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8204b77b-12a6-41d5-99be-3684d0cffebf" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f865e48a-fb10-4533-a2ac-397775ac4b48" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_29713fd0-59e4-4b77-af27-7e7f4312c0ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_06bf5e3b-afa6-40bf-a02d-0f724c739b00" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_29713fd0-59e4-4b77-af27-7e7f4312c0ee" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_29713fd0-59e4-4b77-af27-7e7f4312c0ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_29713fd0-59e4-4b77-af27-7e7f4312c0ee" xlink:to="loc_us-gaap_SegmentDomain_29713fd0-59e4-4b77-af27-7e7f4312c0ee_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_6c3906e9-2000-4907-b52e-5a24102b3b9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_29713fd0-59e4-4b77-af27-7e7f4312c0ee" xlink:to="loc_us-gaap_SegmentDomain_6c3906e9-2000-4907-b52e-5a24102b3b9f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_327b9508-87e0-461d-a031-7a8f0fa11c7a" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6c3906e9-2000-4907-b52e-5a24102b3b9f" xlink:to="loc_cna_CommercialSegmentMember_327b9508-87e0-461d-a031-7a8f0fa11c7a" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="i741d4e064e51440aa8758193b6bec9d0_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_41494e2d-3303-4de8-abac-c331030c0f76" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_daeb4974-db7a-4657-8c3a-d85fb521ea81" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_41494e2d-3303-4de8-abac-c331030c0f76" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_daeb4974-db7a-4657-8c3a-d85fb521ea81" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_91422f9a-579e-45eb-ba65-c79955293085" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_41494e2d-3303-4de8-abac-c331030c0f76" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_91422f9a-579e-45eb-ba65-c79955293085" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_362eaba7-d756-423d-b330-43b19098d96e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_41494e2d-3303-4de8-abac-c331030c0f76" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_362eaba7-d756-423d-b330-43b19098d96e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3538f043-fa34-421a-9825-50c96a82214c" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_41494e2d-3303-4de8-abac-c331030c0f76" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3538f043-fa34-421a-9825-50c96a82214c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_5fc82039-ff63-4fe7-ab80-0d504347b82a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3538f043-fa34-421a-9825-50c96a82214c" xlink:to="loc_srt_ProductOrServiceAxis_5fc82039-ff63-4fe7-ab80-0d504347b82a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5fc82039-ff63-4fe7-ab80-0d504347b82a_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_5fc82039-ff63-4fe7-ab80-0d504347b82a" xlink:to="loc_srt_ProductsAndServicesDomain_5fc82039-ff63-4fe7-ab80-0d504347b82a_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3b286d82-8514-475f-b104-c65bec6253e3" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_5fc82039-ff63-4fe7-ab80-0d504347b82a" xlink:to="loc_srt_ProductsAndServicesDomain_3b286d82-8514-475f-b104-c65bec6253e3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_34cafb67-17ef-4b42-b32e-803f912bdde9" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_3b286d82-8514-475f-b104-c65bec6253e3" xlink:to="loc_cna_WorkersCompensationMember_34cafb67-17ef-4b42-b32e-803f912bdde9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_7299bce4-0b00-47d0-973f-53254f7ecb66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3538f043-fa34-421a-9825-50c96a82214c" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_7299bce4-0b00-47d0-973f-53254f7ecb66" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_7299bce4-0b00-47d0-973f-53254f7ecb66_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_7299bce4-0b00-47d0-973f-53254f7ecb66" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_7299bce4-0b00-47d0-973f-53254f7ecb66_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_7299bce4-0b00-47d0-973f-53254f7ecb66" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_72777fab-9336-4452-90fd-d110b69b5857" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_72777fab-9336-4452-90fd-d110b69b5857" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_66e4be23-ceea-407e-9ee3-7c96d0bad826" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_66e4be23-ceea-407e-9ee3-7c96d0bad826" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_406587e8-cd91-4a03-b5ec-cfc1a1c751ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_406587e8-cd91-4a03-b5ec-cfc1a1c751ae" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_9559121b-7df0-48c0-9a8c-489927e80fe4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_9559121b-7df0-48c0-9a8c-489927e80fe4" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_1c9d4cd0-9048-4df1-9719-3e28beb41118" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_1c9d4cd0-9048-4df1-9719-3e28beb41118" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_51e440e0-0eb4-40ed-a63f-5ea2cd91a190" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_51e440e0-0eb4-40ed-a63f-5ea2cd91a190" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_854c12f3-a9ed-485d-a6d7-15e2b26830ff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_854c12f3-a9ed-485d-a6d7-15e2b26830ff" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a757f6f2-b03b-45bf-a225-12b685388085" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a757f6f2-b03b-45bf-a225-12b685388085" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_26cb4bbe-09ee-41fe-b712-611ce8ac69f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_26cb4bbe-09ee-41fe-b712-611ce8ac69f5" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_30dff1a4-1782-4170-bcde-fa8a3a74ac3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f1012992-4e9a-4138-b9ba-07df21a34356" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_30dff1a4-1782-4170-bcde-fa8a3a74ac3b" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c57f113e-11f6-428f-9571-622132bad05b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3538f043-fa34-421a-9825-50c96a82214c" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c57f113e-11f6-428f-9571-622132bad05b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c57f113e-11f6-428f-9571-622132bad05b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c57f113e-11f6-428f-9571-622132bad05b" xlink:to="loc_us-gaap_SegmentDomain_c57f113e-11f6-428f-9571-622132bad05b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_458cfb3b-b876-4638-8018-755648404140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c57f113e-11f6-428f-9571-622132bad05b" xlink:to="loc_us-gaap_SegmentDomain_458cfb3b-b876-4638-8018-755648404140" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_add50852-91b8-4a94-9dc7-6e57bb0daf33" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_458cfb3b-b876-4638-8018-755648404140" xlink:to="loc_cna_CommercialSegmentMember_add50852-91b8-4a94-9dc7-6e57bb0daf33" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i9ae6a2c4110c4946a9c0cb4895e53680_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_bc2f6389-b56a-438f-9e23-7fcaf0d83202" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_bc2f6389-b56a-438f-9e23-7fcaf0d83202" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_5ad39002-a583-44f6-8f3e-68df4e12af7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_5ad39002-a583-44f6-8f3e-68df4e12af7b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_7e69ce0b-590d-4cd6-8165-e36a17a64505" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_7e69ce0b-590d-4cd6-8165-e36a17a64505" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimAdjustmentExpenseOtherReconcilingItem_f8b10074-9016-4c6c-9907-cd87bef4ed93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimAdjustmentExpenseOtherReconcilingItem"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimAdjustmentExpenseOtherReconcilingItem_f8b10074-9016-4c6c-9907-cd87bef4ed93" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_e65a910f-9334-479d-a18e-4e7d6435d9e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_e65a910f-9334-479d-a18e-4e7d6435d9e3" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_651fac77-497b-416c-a95b-b1b8a9e5cbbe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_651fac77-497b-416c-a95b-b1b8a9e5cbbe" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_d7c47c11-b7b1-4ab5-bd87-70787fef41cd" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_955f04d2-8dad-457c-821b-a2169c6969d3" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_d7c47c11-b7b1-4ab5-bd87-70787fef41cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_f9a195d9-a264-48cc-a7d9-11edc8a192a8" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_d7c47c11-b7b1-4ab5-bd87-70787fef41cd" xlink:to="loc_srt_ProductOrServiceAxis_f9a195d9-a264-48cc-a7d9-11edc8a192a8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f9a195d9-a264-48cc-a7d9-11edc8a192a8_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_f9a195d9-a264-48cc-a7d9-11edc8a192a8" xlink:to="loc_srt_ProductsAndServicesDomain_f9a195d9-a264-48cc-a7d9-11edc8a192a8_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_11201371-ef8f-4586-bc29-dc5a5ee99411" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_f9a195d9-a264-48cc-a7d9-11edc8a192a8" xlink:to="loc_srt_ProductsAndServicesDomain_11201371-ef8f-4586-bc29-dc5a5ee99411" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_6dbf9c51-9047-4c40-8e3e-5305de23c06e" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_11201371-ef8f-4586-bc29-dc5a5ee99411" xlink:to="loc_cna_WorkersCompensationMember_6dbf9c51-9047-4c40-8e3e-5305de23c06e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_84a14837-721f-4a37-9568-37105a34cae0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_d7c47c11-b7b1-4ab5-bd87-70787fef41cd" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_84a14837-721f-4a37-9568-37105a34cae0" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_84a14837-721f-4a37-9568-37105a34cae0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_84a14837-721f-4a37-9568-37105a34cae0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_84a14837-721f-4a37-9568-37105a34cae0_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_84a14837-721f-4a37-9568-37105a34cae0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_6194e8e1-6306-458a-bd0e-89a3913e9d52" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_6194e8e1-6306-458a-bd0e-89a3913e9d52" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_56ab23bb-c3be-4720-af5a-1ad88a05e02c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_56ab23bb-c3be-4720-af5a-1ad88a05e02c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_5c4e12f8-251d-4d34-bab9-675b0a617548" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_5c4e12f8-251d-4d34-bab9-675b0a617548" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_caa8774a-f8cf-4df4-a684-76516b12a284" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_caa8774a-f8cf-4df4-a684-76516b12a284" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_1e7387c1-a77f-4fde-9ef5-17d4e7f50698" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_1e7387c1-a77f-4fde-9ef5-17d4e7f50698" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_8feadbc8-6a1f-45e8-8e14-119dc3f47c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_8feadbc8-6a1f-45e8-8e14-119dc3f47c0a" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_c61558dc-ca50-4ea6-9bcf-754db9fed186" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_c61558dc-ca50-4ea6-9bcf-754db9fed186" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_8faceaad-d135-4557-9894-29daac4b51c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_8faceaad-d135-4557-9894-29daac4b51c5" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_16e7bb17-d960-4204-b4b8-d92f0bced981" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_16e7bb17-d960-4204-b4b8-d92f0bced981" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_9fa8c267-b557-4bdd-be0d-20e51ab03f83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_2d3e924e-e1e6-4e9d-9384-2c60390bbf97" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_9fa8c267-b557-4bdd-be0d-20e51ab03f83" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_b696758a-7ab8-476a-818d-2266594cb6ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_d7c47c11-b7b1-4ab5-bd87-70787fef41cd" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_b696758a-7ab8-476a-818d-2266594cb6ec" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_b696758a-7ab8-476a-818d-2266594cb6ec_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_b696758a-7ab8-476a-818d-2266594cb6ec" xlink:to="loc_us-gaap_SegmentDomain_b696758a-7ab8-476a-818d-2266594cb6ec_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ba3284b9-f55d-4f2e-a3cc-4d2397916729" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_b696758a-7ab8-476a-818d-2266594cb6ec" xlink:to="loc_us-gaap_SegmentDomain_ba3284b9-f55d-4f2e-a3cc-4d2397916729" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_e05c53d3-bd7e-4692-b3c7-5426b76c2e29" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ba3284b9-f55d-4f2e-a3cc-4d2397916729" xlink:to="loc_cna_CommercialSegmentMember_e05c53d3-bd7e-4692-b3c7-5426b76c2e29" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="icacd482e10684cdf92d6c21507743083_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesCommercialWorkersCompensationNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_25928568-ae53-4107-993b-361593761d46" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_25928568-ae53-4107-993b-361593761d46" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AdjustmentforDevelopmentonaDiscountedBasis_6d3328dd-e791-444a-ace0-b569c5139d04" xlink:href="cna-20221231.xsd#cna_AdjustmentforDevelopmentonaDiscountedBasis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_cna_AdjustmentforDevelopmentonaDiscountedBasis_6d3328dd-e791-444a-ace0-b569c5139d04" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_71998cf2-752b-4236-98b9-c57e01794303" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentPriorYears_71998cf2-752b-4236-98b9-c57e01794303" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_67b3e16a-1b4c-4641-ab39-84c22a9fd573" xlink:href="cna-20221231.xsd#cna_UnallocatedClaimAdjustmentExpenseDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_cna_UnallocatedClaimAdjustmentExpenseDevelopment_67b3e16a-1b4c-4641-ab39-84c22a9fd573" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation_59852ec5-c72c-4a4b-86b6-6668bbfa1528" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentWorkersCompensation_59852ec5-c72c-4a4b-86b6-6668bbfa1528" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_674d45ce-55af-4131-a9b1-b62e695da7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_cb96f530-fd75-4189-92c9-839955356a0b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_674d45ce-55af-4131-a9b1-b62e695da7a4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_1a5e7483-f23e-4503-a82e-f273af123e56" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_674d45ce-55af-4131-a9b1-b62e695da7a4" xlink:to="loc_srt_ProductOrServiceAxis_1a5e7483-f23e-4503-a82e-f273af123e56" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1a5e7483-f23e-4503-a82e-f273af123e56_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_1a5e7483-f23e-4503-a82e-f273af123e56" xlink:to="loc_srt_ProductsAndServicesDomain_1a5e7483-f23e-4503-a82e-f273af123e56_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_1020e440-59da-4a62-8164-82357fe74d86" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_1a5e7483-f23e-4503-a82e-f273af123e56" xlink:to="loc_srt_ProductsAndServicesDomain_1020e440-59da-4a62-8164-82357fe74d86" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_3ee547a9-0f72-4c60-9a45-e000e62e4b67" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_1020e440-59da-4a62-8164-82357fe74d86" xlink:to="loc_cna_WorkersCompensationMember_3ee547a9-0f72-4c60-9a45-e000e62e4b67" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_f9f6f8f3-65a1-4361-86ab-98213c0c4b09" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_674d45ce-55af-4131-a9b1-b62e695da7a4" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_f9f6f8f3-65a1-4361-86ab-98213c0c4b09" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f9f6f8f3-65a1-4361-86ab-98213c0c4b09_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_f9f6f8f3-65a1-4361-86ab-98213c0c4b09" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_f9f6f8f3-65a1-4361-86ab-98213c0c4b09_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_f9f6f8f3-65a1-4361-86ab-98213c0c4b09" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_b547b142-7cc7-46ce-b5ad-b49e06721816" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_b547b142-7cc7-46ce-b5ad-b49e06721816" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_ac60d6eb-e2dc-42e6-b819-47c278f3837d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_ac60d6eb-e2dc-42e6-b819-47c278f3837d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_17bcfc92-ac65-410a-9537-c931c7d76430" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_17bcfc92-ac65-410a-9537-c931c7d76430" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_c1540fa0-ad21-4efa-9410-6037beb22ae6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_c1540fa0-ad21-4efa-9410-6037beb22ae6" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_ba0ce6cf-aed3-4ddf-a364-8cdc21fbfe99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_ba0ce6cf-aed3-4ddf-a364-8cdc21fbfe99" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_f76950de-6232-4bee-9fb3-3e5d465fdb07" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_f76950de-6232-4bee-9fb3-3e5d465fdb07" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_2ad8d939-93d1-4a65-bc3d-3fb154bfe0bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_2ad8d939-93d1-4a65-bc3d-3fb154bfe0bc" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_54e40afd-5d78-4d14-99ca-f723854323e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_54e40afd-5d78-4d14-99ca-f723854323e6" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_35784c25-c04e-40de-957b-16e6ca224bdb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d0d0d84e-b86e-45d5-b133-c70f8b157222" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_35784c25-c04e-40de-957b-16e6ca224bdb" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ca9d35db-71b5-42ba-9002-e8c62b1bc07b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_674d45ce-55af-4131-a9b1-b62e695da7a4" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ca9d35db-71b5-42ba-9002-e8c62b1bc07b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ca9d35db-71b5-42ba-9002-e8c62b1bc07b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ca9d35db-71b5-42ba-9002-e8c62b1bc07b" xlink:to="loc_us-gaap_SegmentDomain_ca9d35db-71b5-42ba-9002-e8c62b1bc07b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a49820bd-f495-4bb1-b342-8eed81688920" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ca9d35db-71b5-42ba-9002-e8c62b1bc07b" xlink:to="loc_us-gaap_SegmentDomain_a49820bd-f495-4bb1-b342-8eed81688920" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_3895f3d2-4baa-4996-9f3a-95e83b7e66ee" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a49820bd-f495-4bb1-b342-8eed81688920" xlink:to="loc_cna_CommercialSegmentMember_3895f3d2-4baa-4996-9f3a-95e83b7e66ee" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalNetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalNetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalNetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentDetails" xlink:type="extended" id="i7ee966e8e84547c3afedcc50f0134af1_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalNetprioryearclaimandallocatedclaimadjustmentexpensereservedevelopmentDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_c1069d01-3ba6-4593-bac2-67d50a38e6eb" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentCommercialAuto_c1069d01-3ba6-4593-bac2-67d50a38e6eb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty_ad2af233-d86a-42eb-a7d2-81b2b3e1e5db" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:to="loc_cna_NetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentSpecialty_ad2af233-d86a-42eb-a7d2-81b2b3e1e5db" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability_6a4dfcaf-5fe5-4ae6-a30d-42f833ed0090" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopmentOtherProfessionalLiability_6a4dfcaf-5fe5-4ae6-a30d-42f833ed0090" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_17a2222e-b017-4f8d-9fa9-d916d06f90b9" xlink:href="cna-20221231.xsd#cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:to="loc_cna_PretaxFavorableUnfavorableNetPriorYearClaimAndAllocatedClaimAdjustmentExpenseReserveDevelopmentExcludingLifeGroup_17a2222e-b017-4f8d-9fa9-d916d06f90b9" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_63cab97f-d993-4ed6-99b0-6e3155475af2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_c492a548-bacf-4f03-a959-a3a75e6fca50" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_63cab97f-d993-4ed6-99b0-6e3155475af2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_f4bf31ae-2a8c-483f-86bc-d6ed4db69679" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_63cab97f-d993-4ed6-99b0-6e3155475af2" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_f4bf31ae-2a8c-483f-86bc-d6ed4db69679" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f4bf31ae-2a8c-483f-86bc-d6ed4db69679_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f4bf31ae-2a8c-483f-86bc-d6ed4db69679" xlink:to="loc_us-gaap_SegmentDomain_f4bf31ae-2a8c-483f-86bc-d6ed4db69679_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ae550413-a1f3-477f-a3d8-3c11ea19600d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f4bf31ae-2a8c-483f-86bc-d6ed4db69679" xlink:to="loc_us-gaap_SegmentDomain_ae550413-a1f3-477f-a3d8-3c11ea19600d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_70da2862-7cc5-405c-b22b-af6635a9affd" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_ae550413-a1f3-477f-a3d8-3c11ea19600d" xlink:to="loc_cna_InternationalSegmentMember_70da2862-7cc5-405c-b22b-af6635a9affd" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalShortDurationContractsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalShortDurationContractsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalShortDurationContractsDetails" xlink:type="extended" id="i8a7dab91d2ef4a6f9abed61b4a6c9583_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalShortDurationContractsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_b22aeee4-16c5-4fbe-9124-e1a5ec0a2f06" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_7caddfbc-3e4c-475c-a6ee-776954524f9c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_b22aeee4-16c5-4fbe-9124-e1a5ec0a2f06" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_7caddfbc-3e4c-475c-a6ee-776954524f9c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_e2628ba2-60cc-4072-91ca-e5f9c9bb55e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_b22aeee4-16c5-4fbe-9124-e1a5ec0a2f06" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_e2628ba2-60cc-4072-91ca-e5f9c9bb55e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_87120fdf-260f-4f5a-b2f3-08dc084c4c71" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_e2628ba2-60cc-4072-91ca-e5f9c9bb55e7" xlink:to="loc_srt_ProductOrServiceAxis_87120fdf-260f-4f5a-b2f3-08dc084c4c71" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_87120fdf-260f-4f5a-b2f3-08dc084c4c71_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_87120fdf-260f-4f5a-b2f3-08dc084c4c71" xlink:to="loc_srt_ProductsAndServicesDomain_87120fdf-260f-4f5a-b2f3-08dc084c4c71_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_56fcb86f-cd2e-4b45-ab52-e5c5682865ef" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_87120fdf-260f-4f5a-b2f3-08dc084c4c71" xlink:to="loc_srt_ProductsAndServicesDomain_56fcb86f-cd2e-4b45-ab52-e5c5682865ef" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_57f58def-98eb-4871-8524-4dc00f95662e" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_56fcb86f-cd2e-4b45-ab52-e5c5682865ef" xlink:to="loc_cna_ExcludingHardyMember_57f58def-98eb-4871-8524-4dc00f95662e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_431c5aa5-8026-4aea-a2d4-add9b59f56b4" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_56fcb86f-cd2e-4b45-ab52-e5c5682865ef" xlink:to="loc_cna_HardyMember_431c5aa5-8026-4aea-a2d4-add9b59f56b4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_866f2ca9-9b50-4408-9d5c-1b2df3dce516" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_e2628ba2-60cc-4072-91ca-e5f9c9bb55e7" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_866f2ca9-9b50-4408-9d5c-1b2df3dce516" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_866f2ca9-9b50-4408-9d5c-1b2df3dce516_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_866f2ca9-9b50-4408-9d5c-1b2df3dce516" xlink:to="loc_us-gaap_SegmentDomain_866f2ca9-9b50-4408-9d5c-1b2df3dce516_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_86542270-f7ef-4314-aeda-4a00e87092b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_866f2ca9-9b50-4408-9d5c-1b2df3dce516" xlink:to="loc_us-gaap_SegmentDomain_86542270-f7ef-4314-aeda-4a00e87092b9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_8637f98c-592c-4abd-a0a7-1b851c799667" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_86542270-f7ef-4314-aeda-4a00e87092b9" xlink:to="loc_cna_InternationalSegmentMember_8637f98c-592c-4abd-a0a7-1b851c799667" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="ie7c3c4d711fa4ed29b6a6b93c1b36b83_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_d9c425c3-1030-4524-ba73-5dabef3ce092" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_99fb144e-c230-4779-ae69-acd01ffec30e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_d9c425c3-1030-4524-ba73-5dabef3ce092" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_99fb144e-c230-4779-ae69-acd01ffec30e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_2c252cc9-c213-44ab-a829-81ca9bc41374" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_d9c425c3-1030-4524-ba73-5dabef3ce092" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_2c252cc9-c213-44ab-a829-81ca9bc41374" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_15e2dbf6-df3a-4e17-8ded-470f245a687c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_d9c425c3-1030-4524-ba73-5dabef3ce092" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_15e2dbf6-df3a-4e17-8ded-470f245a687c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_72b79bff-6891-4977-93f2-420b7f2af040" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_d9c425c3-1030-4524-ba73-5dabef3ce092" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_72b79bff-6891-4977-93f2-420b7f2af040" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_72b79bff-6891-4977-93f2-420b7f2af040" xlink:to="loc_srt_ProductOrServiceAxis_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8" xlink:to="loc_srt_ProductsAndServicesDomain_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d141647a-6a75-4041-aa8e-ffd6fac2d0e7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_aac2e250-e9f0-4f23-9f39-d2a758e1a3f8" xlink:to="loc_srt_ProductsAndServicesDomain_d141647a-6a75-4041-aa8e-ffd6fac2d0e7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_d1d0e015-5516-40bd-a163-2468e3c1cc0b" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d141647a-6a75-4041-aa8e-ffd6fac2d0e7" xlink:to="loc_cna_ExcludingHardyMember_d1d0e015-5516-40bd-a163-2468e3c1cc0b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_c3ad3474-ffd4-40cc-b5c0-0742190e93c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_72b79bff-6891-4977-93f2-420b7f2af040" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_c3ad3474-ffd4-40cc-b5c0-0742190e93c1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c3ad3474-ffd4-40cc-b5c0-0742190e93c1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c3ad3474-ffd4-40cc-b5c0-0742190e93c1" xlink:to="loc_us-gaap_SegmentDomain_c3ad3474-ffd4-40cc-b5c0-0742190e93c1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_1eb1f701-0a21-4df4-b6c7-b1cc1cd55c16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_c3ad3474-ffd4-40cc-b5c0-0742190e93c1" xlink:to="loc_us-gaap_SegmentDomain_1eb1f701-0a21-4df4-b6c7-b1cc1cd55c16" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_57cc2287-e1f6-4976-9041-bd870cef1532" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_1eb1f701-0a21-4df4-b6c7-b1cc1cd55c16" xlink:to="loc_cna_InternationalSegmentMember_57cc2287-e1f6-4976-9041-bd870cef1532" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_d9e8e9d4-ba99-4332-a64a-bda9bee75857" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_72b79bff-6891-4977-93f2-420b7f2af040" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_d9e8e9d4-ba99-4332-a64a-bda9bee75857" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d9e8e9d4-ba99-4332-a64a-bda9bee75857_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_d9e8e9d4-ba99-4332-a64a-bda9bee75857" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_d9e8e9d4-ba99-4332-a64a-bda9bee75857_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_d9e8e9d4-ba99-4332-a64a-bda9bee75857" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a467287c-928c-4aea-a183-ca26fc109c7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_a467287c-928c-4aea-a183-ca26fc109c7f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_0ef02ff7-ce5e-4057-b5d5-2d07aa12ba95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_0ef02ff7-ce5e-4057-b5d5-2d07aa12ba95" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_37b10540-e040-499e-b38d-405b3f7a1f9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_37b10540-e040-499e-b38d-405b3f7a1f9b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e1220835-8bc4-4028-bf53-5868caee4bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_e1220835-8bc4-4028-bf53-5868caee4bf2" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_4181dd69-1767-45f7-807a-956243435a0a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_4181dd69-1767-45f7-807a-956243435a0a" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_458667e4-ac64-439a-a754-a6f32c6c8129" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_458667e4-ac64-439a-a754-a6f32c6c8129" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_4c16ddc0-b6f7-4591-8136-12ce38f98876" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_4c16ddc0-b6f7-4591-8136-12ce38f98876" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_2011a10a-840c-4eb2-9717-74eb11ee722e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_2011a10a-840c-4eb2-9717-74eb11ee722e" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_4ce648f7-f153-4af4-a41a-ca0ad5a9018e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_4ce648f7-f153-4af4-a41a-ca0ad5a9018e" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_09545caa-fa2b-4f7f-bfb6-c210e83ea0fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_85e341ed-cda9-4f80-bca1-5a26b0138606" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_09545caa-fa2b-4f7f-bfb6-c210e83ea0fb" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="i486deec319f245ecbcce7ee42d47d032_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c62c27a4-7c24-4ae6-8ee1-f01b1a6825a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_c62c27a4-7c24-4ae6-8ee1-f01b1a6825a4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_d7b31925-8b48-4592-89b3-ea575630b716" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_d7b31925-8b48-4592-89b3-ea575630b716" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_f0ec8b5f-9fa1-4c09-97fa-4fa8156ae897" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_f0ec8b5f-9fa1-4c09-97fa-4fa8156ae897" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_ba5993a5-7886-432e-9207-f9fb4169872e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_ba5993a5-7886-432e-9207-f9fb4169872e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_6d119678-ecfb-4ad6-9289-b9f417dc4492" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_6d119678-ecfb-4ad6-9289-b9f417dc4492" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_ee2c1e1e-ea99-475a-8f57-64c1f3effe5a" xlink:href="cna-20221231.xsd#cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesLineItems_319f32e8-8cd8-47a7-bbc1-de8ca7e9aad9" xlink:to="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_ee2c1e1e-ea99-475a-8f57-64c1f3effe5a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_ee2c1e1e-ea99-475a-8f57-64c1f3effe5a" xlink:to="loc_srt_ProductOrServiceAxis_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3" xlink:to="loc_srt_ProductsAndServicesDomain_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_bc8a0ef9-99de-4e6c-9efa-c5d1e9cf7001" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_3312ab85-0e84-4f7c-a4ac-b2b8cd495ef3" xlink:to="loc_srt_ProductsAndServicesDomain_bc8a0ef9-99de-4e6c-9efa-c5d1e9cf7001" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_2251caf8-9913-4d6f-9ed5-74629348e0ee" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_bc8a0ef9-99de-4e6c-9efa-c5d1e9cf7001" xlink:to="loc_cna_ExcludingHardyMember_2251caf8-9913-4d6f-9ed5-74629348e0ee" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e01442a9-65eb-48a6-849a-ce8ed20c8e13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_ee2c1e1e-ea99-475a-8f57-64c1f3effe5a" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e01442a9-65eb-48a6-849a-ce8ed20c8e13" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e01442a9-65eb-48a6-849a-ce8ed20c8e13_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e01442a9-65eb-48a6-849a-ce8ed20c8e13" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_e01442a9-65eb-48a6-849a-ce8ed20c8e13_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_e01442a9-65eb-48a6-849a-ce8ed20c8e13" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_44142b66-3382-4b93-877f-7cc8db844b12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_44142b66-3382-4b93-877f-7cc8db844b12" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_156406c6-91e0-4b72-81a5-8de91deb62ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_156406c6-91e0-4b72-81a5-8de91deb62ab" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_e191fea3-6b45-4b66-a21b-d39ee92b5da2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_e191fea3-6b45-4b66-a21b-d39ee92b5da2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_0b9978e6-9ecf-433d-9a57-43930e21b702" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_0b9978e6-9ecf-433d-9a57-43930e21b702" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_08ba81ba-dc8f-4b74-a7cf-a0e1bcd60772" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_08ba81ba-dc8f-4b74-a7cf-a0e1bcd60772" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_00302f0d-fffb-428d-b84a-d0698f4285e7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_00302f0d-fffb-428d-b84a-d0698f4285e7" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_1ee6de4e-9447-46a3-962f-4871d528317e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_1ee6de4e-9447-46a3-962f-4871d528317e" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a22bb418-db8a-4d44-9fdc-f5ea43217699" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_a22bb418-db8a-4d44-9fdc-f5ea43217699" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f4f9919a-6e43-404f-b6ee-245e0e6b84d8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_f4f9919a-6e43-404f-b6ee-245e0e6b84d8" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_aaad1566-a14e-4735-8ad2-085d4f91a2ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_5615a785-1461-4ddd-9bfe-d1d5faceaf1b" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_aaad1566-a14e-4735-8ad2-085d4f91a2ba" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9ed31a51-f832-4186-93a6-cd523fa9e7e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationInsuranceContractsNetCumulativePaidClaimandClaimAdjustmentExpensesTable_ee2c1e1e-ea99-475a-8f57-64c1f3effe5a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9ed31a51-f832-4186-93a6-cd523fa9e7e8" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9ed31a51-f832-4186-93a6-cd523fa9e7e8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9ed31a51-f832-4186-93a6-cd523fa9e7e8" xlink:to="loc_us-gaap_SegmentDomain_9ed31a51-f832-4186-93a6-cd523fa9e7e8_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_c06171f8-42fd-4f1f-86e7-99a005245cab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9ed31a51-f832-4186-93a6-cd523fa9e7e8" xlink:to="loc_us-gaap_SegmentDomain_c06171f8-42fd-4f1f-86e7-99a005245cab" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_56fd5df2-f1ec-4eee-aa23-ec9b25ff51b7" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_c06171f8-42fd-4f1f-86e7-99a005245cab" xlink:to="loc_cna_InternationalSegmentMember_56fd5df2-f1ec-4eee-aa23-ec9b25ff51b7" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="ie236c30e3b2a4c4680535ec20cb094ba_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalExcludingHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_d344edcf-2e15-44c5-a2fe-3602445d1a84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_918140dd-44f1-4e75-ba0e-19972274fe07" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_d344edcf-2e15-44c5-a2fe-3602445d1a84" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_918140dd-44f1-4e75-ba0e-19972274fe07" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_157d5974-efcc-45c3-bd71-0f63779be40e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_d344edcf-2e15-44c5-a2fe-3602445d1a84" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_157d5974-efcc-45c3-bd71-0f63779be40e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_82c5d5f6-8eb9-47c5-bd20-b950d312da53" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_157d5974-efcc-45c3-bd71-0f63779be40e" xlink:to="loc_srt_ProductOrServiceAxis_82c5d5f6-8eb9-47c5-bd20-b950d312da53" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_82c5d5f6-8eb9-47c5-bd20-b950d312da53_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_82c5d5f6-8eb9-47c5-bd20-b950d312da53" xlink:to="loc_srt_ProductsAndServicesDomain_82c5d5f6-8eb9-47c5-bd20-b950d312da53_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f1849857-efe0-4df3-b648-3d9bf472b1cd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_82c5d5f6-8eb9-47c5-bd20-b950d312da53" xlink:to="loc_srt_ProductsAndServicesDomain_f1849857-efe0-4df3-b648-3d9bf472b1cd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_f37b46d6-ca89-4ad5-8d47-73a4d19da889" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_f1849857-efe0-4df3-b648-3d9bf472b1cd" xlink:to="loc_cna_ExcludingHardyMember_f37b46d6-ca89-4ad5-8d47-73a4d19da889" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_157d5974-efcc-45c3-bd71-0f63779be40e" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_41e2e4f0-4739-4932-8f6c-6d1770a3e6c4" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_7138ebc2-1c5a-48b4-80c3-8518dc83cd91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_7138ebc2-1c5a-48b4-80c3-8518dc83cd91" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_86470959-2529-4771-aa09-75a328086101" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_86470959-2529-4771-aa09-75a328086101" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d19ac69a-b0b4-483c-917d-12627a2396b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_d19ac69a-b0b4-483c-917d-12627a2396b1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_759d0f48-74cb-414a-9713-eca75aa29832" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_759d0f48-74cb-414a-9713-eca75aa29832" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_aa566240-27aa-4c9d-b774-20cf9a09ec98" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_aa566240-27aa-4c9d-b774-20cf9a09ec98" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_cad68491-aea5-4399-9181-53a6bfc6bac4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_cad68491-aea5-4399-9181-53a6bfc6bac4" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_a69c2c68-8922-4830-a4c0-cd72ba6e3806" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_a69c2c68-8922-4830-a4c0-cd72ba6e3806" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_695d0117-6948-4f3b-a421-6a3037cc7154" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_695d0117-6948-4f3b-a421-6a3037cc7154" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_d609a3e0-6b1e-4c73-a1a1-58e8d4ecf6d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_87040241-d019-47f5-a1f1-044fdf5c8163" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_d609a3e0-6b1e-4c73-a1a1-58e8d4ecf6d4" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_82029425-1054-4141-a50c-6755a4b81f95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_157d5974-efcc-45c3-bd71-0f63779be40e" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_82029425-1054-4141-a50c-6755a4b81f95" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_82029425-1054-4141-a50c-6755a4b81f95_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_82029425-1054-4141-a50c-6755a4b81f95" xlink:to="loc_us-gaap_SegmentDomain_82029425-1054-4141-a50c-6755a4b81f95_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d8826fa0-f804-402f-9967-42346c2c3188" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_82029425-1054-4141-a50c-6755a4b81f95" xlink:to="loc_us-gaap_SegmentDomain_d8826fa0-f804-402f-9967-42346c2c3188" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_fd76d217-de0b-4da2-840c-3c114863a4f4" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_d8826fa0-f804-402f-9967-42346c2c3188" xlink:to="loc_cna_InternationalSegmentMember_fd76d217-de0b-4da2-840c-3c114863a4f4" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails" xlink:type="extended" id="i4bc4a48cd3994d5da5ef6aa8b6d47f28_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetIncurredClaimsandAllocatedClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_cc320304-f7e0-4bd8-b2ed-356a55b2721f" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_9f24df5b-b830-48d8-abe2-df867161b212" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_cc320304-f7e0-4bd8-b2ed-356a55b2721f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet_9f24df5b-b830-48d8-abe2-df867161b212" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_913bb8f9-37c7-43f9-b07c-74d874026142" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_cc320304-f7e0-4bd8-b2ed-356a55b2721f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet_913bb8f9-37c7-43f9-b07c-74d874026142" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_e0ff2761-2ca3-4dd2-a600-8cd7b535706e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_cc320304-f7e0-4bd8-b2ed-356a55b2721f" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsNumberOfReportedClaims_e0ff2761-2ca3-4dd2-a600-8cd7b535706e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3d22be88-e397-473b-a906-d9916caf747d" xlink:href="cna-20221231.xsd#cna_NetIncurredClaimandClaimAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseLineItems_cc320304-f7e0-4bd8-b2ed-356a55b2721f" xlink:to="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3d22be88-e397-473b-a906-d9916caf747d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_25f566e7-ab0e-4794-9313-8de3923721de" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3d22be88-e397-473b-a906-d9916caf747d" xlink:to="loc_srt_ProductOrServiceAxis_25f566e7-ab0e-4794-9313-8de3923721de" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_25f566e7-ab0e-4794-9313-8de3923721de_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_25f566e7-ab0e-4794-9313-8de3923721de" xlink:to="loc_srt_ProductsAndServicesDomain_25f566e7-ab0e-4794-9313-8de3923721de_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7bd97e9e-36e5-4422-9ee4-e28d7f737e4d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_25f566e7-ab0e-4794-9313-8de3923721de" xlink:to="loc_srt_ProductsAndServicesDomain_7bd97e9e-36e5-4422-9ee4-e28d7f737e4d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_058f5938-f9f3-4568-ad45-d03a2bbc5468" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7bd97e9e-36e5-4422-9ee4-e28d7f737e4d" xlink:to="loc_cna_HardyMember_058f5938-f9f3-4568-ad45-d03a2bbc5468" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_ac35ae6d-702f-48d5-b17b-aed8189d5b97" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7bd97e9e-36e5-4422-9ee4-e28d7f737e4d" xlink:to="loc_cna_ExcludingHardyMember_ac35ae6d-702f-48d5-b17b-aed8189d5b97" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9fe61b90-aa77-458c-a548-b9028567fab4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3d22be88-e397-473b-a906-d9916caf747d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9fe61b90-aa77-458c-a548-b9028567fab4" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9fe61b90-aa77-458c-a548-b9028567fab4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9fe61b90-aa77-458c-a548-b9028567fab4" xlink:to="loc_us-gaap_SegmentDomain_9fe61b90-aa77-458c-a548-b9028567fab4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_124770dc-a55b-45f7-893d-2c0e0ff16208" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9fe61b90-aa77-458c-a548-b9028567fab4" xlink:to="loc_us-gaap_SegmentDomain_124770dc-a55b-45f7-893d-2c0e0ff16208" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_887e5806-9265-4ee2-a43c-45c671a28c93" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_124770dc-a55b-45f7-893d-2c0e0ff16208" xlink:to="loc_cna_InternationalSegmentMember_887e5806-9265-4ee2-a43c-45c671a28c93" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_360c1322-3da1-4383-9184-96e989c30862" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_NetIncurredClaimandClaimAdjustmentExpenseTable_3d22be88-e397-473b-a906-d9916caf747d" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_360c1322-3da1-4383-9184-96e989c30862" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_360c1322-3da1-4383-9184-96e989c30862_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_360c1322-3da1-4383-9184-96e989c30862" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_360c1322-3da1-4383-9184-96e989c30862_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_360c1322-3da1-4383-9184-96e989c30862" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_71ec7fd9-1abb-49bc-bbf6-5209d0bff0fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_71ec7fd9-1abb-49bc-bbf6-5209d0bff0fc" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_8bd4fbb3-b662-4255-ad47-e519df65bcf6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_8bd4fbb3-b662-4255-ad47-e519df65bcf6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_b95fb858-3be7-48ef-8161-06d3e510bf7e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_b95fb858-3be7-48ef-8161-06d3e510bf7e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_8d6e10cf-bc03-404a-9ee4-4e795e9e854d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_8d6e10cf-bc03-404a-9ee4-4e795e9e854d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_f8b5bdc7-db49-4900-8e94-83fa489e0296" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_f8b5bdc7-db49-4900-8e94-83fa489e0296" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_55467cb3-c00b-4b83-aaa1-4c80399aee86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_55467cb3-c00b-4b83-aaa1-4c80399aee86" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_fa30b037-1afb-4359-a07a-33cc03e22a01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_fa30b037-1afb-4359-a07a-33cc03e22a01" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_3446d997-7a64-41a8-a200-b0fb6435ca4d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_3446d997-7a64-41a8-a200-b0fb6435ca4d" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_87e14fc1-126a-4727-8b12-977032b7ba6d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_87e14fc1-126a-4727-8b12-977032b7ba6d" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_961c4ee1-7374-4626-9755-dc93abb138d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a332419b-97f4-44cf-b8ef-969c35e915a2" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_961c4ee1-7374-4626-9755-dc93abb138d9" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails" xlink:type="extended" id="idf71f184808a488e84bae99a4b7ca2ae_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetCumulativePaidClaimandClaimAdjustmentExpensesDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_f6b968a3-cee0-48b3-9ed9-2229bbbf7262" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet_f6b968a3-cee0-48b3-9ed9-2229bbbf7262" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_35567c33-51f0-4e85-a397-4d012af7fae5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet_35567c33-51f0-4e85-a397-4d012af7fae5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_c6cc8c5c-8520-4f4f-a0dc-9588b4b062a5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented_c6cc8c5c-8520-4f4f-a0dc-9588b4b062a5" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_891f23e5-b88d-4aa5-929b-70dbf9385d80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_891f23e5-b88d-4aa5-929b-70dbf9385d80" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_7c6fe711-90d4-4ab2-978d-d2a17bc6e181" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet_7c6fe711-90d4-4ab2-978d-d2a17bc6e181" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_accc5484-9e50-4f41-bbe6-5bd4779fb541" xlink:href="cna-20221231.xsd#cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesLineItems_ab23afa7-27ca-4895-96b9-1637cbd96ab0" xlink:to="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_accc5484-9e50-4f41-bbe6-5bd4779fb541" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_accc5484-9e50-4f41-bbe6-5bd4779fb541" xlink:to="loc_srt_ProductOrServiceAxis_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c" xlink:to="loc_srt_ProductsAndServicesDomain_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5f14e9e7-b25d-4acb-b033-ebd1278659be" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_3d5c8194-1a54-441f-b7d9-f22c4e2aaf5c" xlink:to="loc_srt_ProductsAndServicesDomain_5f14e9e7-b25d-4acb-b033-ebd1278659be" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_4592c260-7eda-44eb-be40-a554f864796e" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5f14e9e7-b25d-4acb-b033-ebd1278659be" xlink:to="loc_cna_HardyMember_4592c260-7eda-44eb-be40-a554f864796e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_ec38844f-7ad7-4667-9616-bcd97d1a71c7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_accc5484-9e50-4f41-bbe6-5bd4779fb541" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_ec38844f-7ad7-4667-9616-bcd97d1a71c7" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_ec38844f-7ad7-4667-9616-bcd97d1a71c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ec38844f-7ad7-4667-9616-bcd97d1a71c7" xlink:to="loc_us-gaap_SegmentDomain_ec38844f-7ad7-4667-9616-bcd97d1a71c7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_56339253-fde3-4823-aaab-199eb8077b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_ec38844f-7ad7-4667-9616-bcd97d1a71c7" xlink:to="loc_us-gaap_SegmentDomain_56339253-fde3-4823-aaab-199eb8077b2c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_f27db88a-0d68-4d8d-8a41-d5ef15f7a19a" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_56339253-fde3-4823-aaab-199eb8077b2c" xlink:to="loc_cna_InternationalSegmentMember_f27db88a-0d68-4d8d-8a41-d5ef15f7a19a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ShortDurationContractsNetCumulativePaidClaimAdjustmentExpensesTable_accc5484-9e50-4f41-bbe6-5bd4779fb541" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_65707f1c-9c6d-401c-8e4d-3a596a0e6b0b" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_b1545b1e-4dae-48d3-8747-49c5e28a3367" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_b1545b1e-4dae-48d3-8747-49c5e28a3367" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_19bf482d-edbc-4d10-9c30-86416e724541" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_19bf482d-edbc-4d10-9c30-86416e724541" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_f35e86ff-be4a-4376-8b3e-22b32f965d13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_f35e86ff-be4a-4376-8b3e-22b32f965d13" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_a41dda66-281d-4fa9-ba63-ae73c448baa0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_a41dda66-281d-4fa9-ba63-ae73c448baa0" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_2ebc9c08-1937-4e1a-99e6-265b486a4f94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_2ebc9c08-1937-4e1a-99e6-265b486a4f94" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_370871b9-1b3f-40c0-93b8-3c53ed469bce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_370871b9-1b3f-40c0-93b8-3c53ed469bce" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_37f105bb-5c21-46dd-a99d-db301752d79b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_37f105bb-5c21-46dd-a99d-db301752d79b" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_c50efd7a-7a3f-42ac-a84b-f651d63871a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_c50efd7a-7a3f-42ac-a84b-f651d63871a9" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_9fae56e9-23d1-4db1-a776-63a7b1fbb683" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_9fae56e9-23d1-4db1-a776-63a7b1fbb683" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_d2c7dac1-427f-4a1c-a948-74eb0a40e0bf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2022Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_a27cc7fc-d9d6-462b-a4cd-a485e71f9a91" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2022Member_d2c7dac1-427f-4a1c-a948-74eb0a40e0bf" xlink:type="arc" order="9"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails" xlink:type="extended" id="ie450eb68f4f14bd0abd23b35ddb058ba_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesInternationalHardyNetStrengtheningorReleasingofPriorAccidentYearReservesDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_29f33e0c-b070-4446-b428-7bc7db019814" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_c6abee92-0607-41c4-aa97-3b9a4c2b25ff" xlink:href="cna-20221231.xsd#cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_29f33e0c-b070-4446-b428-7bc7db019814" xlink:to="loc_cna_NetPriorYearClaimandAllocatedClaimAdjustmentExpenseReserveDevelopment_c6abee92-0607-41c4-aa97-3b9a4c2b25ff" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_16331548-2fc5-4479-acda-df625aeccebf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityLineItems_29f33e0c-b070-4446-b428-7bc7db019814" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_16331548-2fc5-4479-acda-df625aeccebf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_3d7ece7d-3c47-48e9-ac83-71b956c330ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_16331548-2fc5-4479-acda-df625aeccebf" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_3d7ece7d-3c47-48e9-ac83-71b956c330ac" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_3d7ece7d-3c47-48e9-ac83-71b956c330ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3d7ece7d-3c47-48e9-ac83-71b956c330ac" xlink:to="loc_us-gaap_SegmentDomain_3d7ece7d-3c47-48e9-ac83-71b956c330ac_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_4984d3e4-1e75-4837-b1ff-148af3567734" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_3d7ece7d-3c47-48e9-ac83-71b956c330ac" xlink:to="loc_us-gaap_SegmentDomain_4984d3e4-1e75-4837-b1ff-148af3567734" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_46ef363d-6707-4301-9b20-127ec099b4bf" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_4984d3e4-1e75-4837-b1ff-148af3567734" xlink:to="loc_cna_InternationalSegmentMember_46ef363d-6707-4301-9b20-127ec099b4bf" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_0e252810-9d65-4a35-8823-7565ac26cd61" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_16331548-2fc5-4479-acda-df625aeccebf" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_0e252810-9d65-4a35-8823-7565ac26cd61" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_0e252810-9d65-4a35-8823-7565ac26cd61_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_0e252810-9d65-4a35-8823-7565ac26cd61" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_0e252810-9d65-4a35-8823-7565ac26cd61_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYearDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_0e252810-9d65-4a35-8823-7565ac26cd61" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_50491d41-1412-4547-9643-b8e2a07b3ef7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member_50491d41-1412-4547-9643-b8e2a07b3ef7" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_b03c2fdc-a989-4103-b51e-f1de5be0612f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member_b03c2fdc-a989-4103-b51e-f1de5be0612f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_1ecd37d0-7d1d-4c6a-b83e-5f8464ba8116" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member_1ecd37d0-7d1d-4c6a-b83e-5f8464ba8116" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_f600495d-cff6-46fc-9822-e2b68b76f929" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_f600495d-cff6-46fc-9822-e2b68b76f929" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_24d0f9da-bf90-4dd5-87b9-d6dc99abefd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member_24d0f9da-bf90-4dd5-87b9-d6dc99abefd5" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_3d3877be-ec20-4196-852f-8f67679a2922" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member_3d3877be-ec20-4196-852f-8f67679a2922" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_f01cc600-76cc-4a3f-9b17-577c26c92c59" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2019Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2019Member_f01cc600-76cc-4a3f-9b17-577c26c92c59" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_53543e71-0bc3-4846-9121-18759f3008fe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2020Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2020Member_53543e71-0bc3-4846-9121-18759f3008fe" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_4a8dff5a-1e43-4ea8-941b-e8e606563c07" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortDurationInsuranceContractAccidentYear2021Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_00cef914-0a62-4c23-beec-d9c73c21e194" xlink:to="loc_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_4a8dff5a-1e43-4ea8-941b-e8e606563c07" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_097fbbdd-483a-40cd-9174-b35eae1d2613" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsReconciliationOfClaimsDevelopmentToLiabilityTable_16331548-2fc5-4479-acda-df625aeccebf" xlink:to="loc_srt_ProductOrServiceAxis_097fbbdd-483a-40cd-9174-b35eae1d2613" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_097fbbdd-483a-40cd-9174-b35eae1d2613_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_097fbbdd-483a-40cd-9174-b35eae1d2613" xlink:to="loc_srt_ProductsAndServicesDomain_097fbbdd-483a-40cd-9174-b35eae1d2613_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ae47e587-29c8-4664-88ee-c3b9cb12841e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_097fbbdd-483a-40cd-9174-b35eae1d2613" xlink:to="loc_srt_ProductsAndServicesDomain_ae47e587-29c8-4664-88ee-c3b9cb12841e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_769a2d3c-2b72-4870-a9fa-52938b40d554" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_ae47e587-29c8-4664-88ee-c3b9cb12841e" xlink:to="loc_cna_HardyMember_769a2d3c-2b72-4870-a9fa-52938b40d554" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesHistoricalClaimsDurationDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesHistoricalClaimsDurationDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesHistoricalClaimsDurationDetails" xlink:type="extended" id="ic48b38efb70d4b7a8db22dd8fe33f34c_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesHistoricalClaimsDurationDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne_56bc5da9-02ba-436a-bb91-9318ee91b5d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearOne_56bc5da9-02ba-436a-bb91-9318ee91b5d5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo_710070ef-43a1-4f9c-acfd-83809e8e1de1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTwo_710070ef-43a1-4f9c-acfd-83809e8e1de1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree_9bc0adc3-ec0f-487d-bda3-77ede2d14a39" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearThree_9bc0adc3-ec0f-487d-bda3-77ede2d14a39" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour_8c873c97-56bf-4618-9f13-e7389532ed49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFour_8c873c97-56bf-4618-9f13-e7389532ed49" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive_82cf14b9-660c-4f2e-83f2-818c6d308813" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearFive_82cf14b9-660c-4f2e-83f2-818c6d308813" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix_2298bd55-6011-4462-b6d1-d6e1c46b0d75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSix_2298bd55-6011-4462-b6d1-d6e1c46b0d75" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven_5148684b-992c-4386-b0d9-e7cae903b059" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearSeven_5148684b-992c-4386-b0d9-e7cae903b059" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight_cfb6a7d4-9805-441a-b04b-6af5eb3b5bba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearEight_cfb6a7d4-9805-441a-b04b-6af5eb3b5bba" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine_e17b29fe-b452-413e-9384-01c0b4e49287" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearNine_e17b29fe-b452-413e-9384-01c0b4e49287" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen_d0a3a6c7-0e64-49c1-8f57-bfa8c61d3117" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationYearTen_d0a3a6c7-0e64-49c1-8f57-bfa8c61d3117" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_4f796f52-0515-41b2-8a90-29dcc2b3e918" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationLineItems_38692da3-060e-4717-8321-7696ac2b0ef2" xlink:to="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_4f796f52-0515-41b2-8a90-29dcc2b3e918" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8fe687f4-8704-444a-b226-cbe75c8fadb0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_4f796f52-0515-41b2-8a90-29dcc2b3e918" xlink:to="loc_srt_ProductOrServiceAxis_8fe687f4-8704-444a-b226-cbe75c8fadb0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8fe687f4-8704-444a-b226-cbe75c8fadb0_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8fe687f4-8704-444a-b226-cbe75c8fadb0" xlink:to="loc_srt_ProductsAndServicesDomain_8fe687f4-8704-444a-b226-cbe75c8fadb0_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8fe687f4-8704-444a-b226-cbe75c8fadb0" xlink:to="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MedicalProfessionalLiabilityMember_26999719-4440-46ab-9180-5c51723f7fab" xlink:href="cna-20221231.xsd#cna_MedicalProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_MedicalProfessionalLiabilityMember_26999719-4440-46ab-9180-5c51723f7fab" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_3d5af371-5e45-42e9-8aaf-70dfaa19fecd" xlink:href="cna-20221231.xsd#cna_OtherProfessionalLiabilityandManagementLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_OtherProfessionalLiabilityandManagementLiabilityMember_3d5af371-5e45-42e9-8aaf-70dfaa19fecd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_e763b959-5c16-44ac-bce3-2c651ba56965" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_SuretyMember_e763b959-5c16-44ac-bce3-2c651ba56965" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialAutoProductLineMember_4104a18a-0d5a-4cfd-b314-599226420c0e" xlink:href="cna-20221231.xsd#cna_CommercialAutoProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_CommercialAutoProductLineMember_4104a18a-0d5a-4cfd-b314-599226420c0e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralLiabilityMember_0eab9c39-e873-4b17-b8a0-1712dd18fe4d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_us-gaap_GeneralLiabilityMember_0eab9c39-e873-4b17-b8a0-1712dd18fe4d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WorkersCompensationMember_32083d3c-9cb4-4e68-b16d-51c1c4e9caae" xlink:href="cna-20221231.xsd#cna_WorkersCompensationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_WorkersCompensationMember_32083d3c-9cb4-4e68-b16d-51c1c4e9caae" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ExcludingHardyMember_d7db402c-4433-485c-9d88-a7a7e1e7b880" xlink:href="cna-20221231.xsd#cna_ExcludingHardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_ExcludingHardyMember_d7db402c-4433-485c-9d88-a7a7e1e7b880" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_7ee052e8-0a50-4ced-9cc8-331b7d240f75" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d248ffd8-1e05-4817-82db-a71abd07dcb7" xlink:to="loc_cna_HardyMember_7ee052e8-0a50-4ced-9cc8-331b7d240f75" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_f7aaf674-4566-4610-87a4-f7a1156a2987" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ShortdurationInsuranceContractsHistoricalClaimsDurationTable_4f796f52-0515-41b2-8a90-29dcc2b3e918" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_f7aaf674-4566-4610-87a4-f7a1156a2987" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f7aaf674-4566-4610-87a4-f7a1156a2987_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f7aaf674-4566-4610-87a4-f7a1156a2987" xlink:to="loc_us-gaap_SegmentDomain_f7aaf674-4566-4610-87a4-f7a1156a2987_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9acc2dfb-d409-489e-b964-d3f12ce450f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f7aaf674-4566-4610-87a4-f7a1156a2987" xlink:to="loc_us-gaap_SegmentDomain_9acc2dfb-d409-489e-b964-d3f12ce450f0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_244564e0-ed4c-4f28-a923-fc5b95f10e20" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9acc2dfb-d409-489e-b964-d3f12ce450f0" xlink:to="loc_cna_SpecialtySegmentMember_244564e0-ed4c-4f28-a923-fc5b95f10e20" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_1b6c102f-34ad-4503-8335-a6348b86259a" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9acc2dfb-d409-489e-b964-d3f12ce450f0" xlink:to="loc_cna_CommercialSegmentMember_1b6c102f-34ad-4503-8335-a6348b86259a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_f33b9086-99b2-48f1-ba14-a2ce4b6534ab" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9acc2dfb-d409-489e-b964-d3f12ce450f0" xlink:to="loc_cna_InternationalSegmentMember_f33b9086-99b2-48f1-ba14-a2ce4b6534ab" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesImpactofLossPortfolioTransferontheConsolidatedStatementofOperationsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesImpactofLossPortfolioTransferontheConsolidatedStatementofOperationsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesImpactofLossPortfolioTransferontheConsolidatedStatementofOperationsDetails" xlink:type="extended" id="ief270f1879c34c1ca45d2096c6455ff7_ClaimandClaimAdjustmentExpenseReservesandFuturePolicyBenefitReservesImpactofLossPortfolioTransferontheConsolidatedStatementofOperationsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetAEPadversedevelopmentbeforeconsiderationofLPT_d5f0bc0e-6e76-43d4-bd7d-e603bd93be19" xlink:href="cna-20221231.xsd#cna_NetAEPadversedevelopmentbeforeconsiderationofLPT"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_cna_NetAEPadversedevelopmentbeforeconsiderationofLPT_d5f0bc0e-6e76-43d4-bd7d-e603bd93be19" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ProvisionForUncollectibleThirdPartyReinsurance_e47b5bf8-b34a-4834-9092-d7aaac292876" xlink:href="cna-20221231.xsd#cna_ProvisionForUncollectibleThirdPartyReinsurance"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_cna_ProvisionForUncollectibleThirdPartyReinsurance_e47b5bf8-b34a-4834-9092-d7aaac292876" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PolicyholderBenefitsandClaimsIncurredAdditionalAmountCeded_67504182-cac8-4e4d-a8c4-6715eddc686c" xlink:href="cna-20221231.xsd#cna_PolicyholderBenefitsandClaimsIncurredAdditionalAmountCeded"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_cna_PolicyholderBenefitsandClaimsIncurredAdditionalAmountCeded_67504182-cac8-4e4d-a8c4-6715eddc686c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Retroactivereinsurancebenefitrecognized_b4bf58f5-4e71-48a2-ab40-8a1726aaf3eb" xlink:href="cna-20221231.xsd#cna_Retroactivereinsurancebenefitrecognized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_cna_Retroactivereinsurancebenefitrecognized_b4bf58f5-4e71-48a2-ab40-8a1726aaf3eb" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Pretaximpactofdeferredretroactivereinsurancebenefit_e0e40bf9-567c-4ddf-a372-73c0a9900377" xlink:href="cna-20221231.xsd#cna_Pretaximpactofdeferredretroactivereinsurancebenefit"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_cna_Pretaximpactofdeferredretroactivereinsurancebenefit_e0e40bf9-567c-4ddf-a372-73c0a9900377" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_b6b772f8-69ba-497a-954a-59cc4968593a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseLineItems_5f0d96af-0683-4559-a780-0fe10255efe2" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_b6b772f8-69ba-497a-954a-59cc4968593a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_a390537e-9313-4e7a-a03b-a1ca59802da2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseTable_b6b772f8-69ba-497a-954a-59cc4968593a" xlink:to="loc_srt_ProductOrServiceAxis_a390537e-9313-4e7a-a03b-a1ca59802da2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_a390537e-9313-4e7a-a03b-a1ca59802da2_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_a390537e-9313-4e7a-a03b-a1ca59802da2" xlink:to="loc_srt_ProductsAndServicesDomain_a390537e-9313-4e7a-a03b-a1ca59802da2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8ad5b7b5-ef47-4cf9-b131-20f5e31c6bea" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_a390537e-9313-4e7a-a03b-a1ca59802da2" xlink:to="loc_srt_ProductsAndServicesDomain_8ad5b7b5-ef47-4cf9-b131-20f5e31c6bea" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AsbestosandEnvironmentalReservesMember_484b9910-4294-484d-8223-5ae330de9772" xlink:href="cna-20221231.xsd#cna_AsbestosandEnvironmentalReservesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8ad5b7b5-ef47-4cf9-b131-20f5e31c6bea" xlink:to="loc_cna_AsbestosandEnvironmentalReservesMember_484b9910-4294-484d-8223-5ae330de9772" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/LegalProceedingsContingenciesandGuaranteesNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#LegalProceedingsContingenciesandGuaranteesNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/LegalProceedingsContingenciesandGuaranteesNarrativeDetails" xlink:type="extended" id="iae85b340af1d49d2873b9f6dd5ca61fb_LegalProceedingsContingenciesandGuaranteesNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesLineItems_d133f1d1-e10d-45ba-b5f2-900caac0e88a" xlink:href="cna-20221231.xsd#cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_04368bd9-8e80-4884-b9cf-f996396d2be8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesLineItems_d133f1d1-e10d-45ba-b5f2-900caac0e88a" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_04368bd9-8e80-4884-b9cf-f996396d2be8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesTable_b0a25beb-5355-40a9-854e-b2da7ccf0e2d" xlink:href="cna-20221231.xsd#cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesLineItems_d133f1d1-e10d-45ba-b5f2-900caac0e88a" xlink:to="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesTable_b0a25beb-5355-40a9-854e-b2da7ccf0e2d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_LegalProceedingsCommitmentsandContingenciesandGuaranteesTable_b0a25beb-5355-40a9-854e-b2da7ccf0e2d" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_0cf9d228-2b54-4f62-a3f0-15150e6eacf2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_e5cccd4a-9fbc-47e7-b3ae-8bddc354fe95" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_0cf9d228-2b54-4f62-a3f0-15150e6eacf2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMember_6fcac0fd-e812-4253-9cdc-92d52eaf9f1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GuaranteeObligationsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_0cf9d228-2b54-4f62-a3f0-15150e6eacf2" xlink:to="loc_us-gaap_GuaranteeObligationsMember_6fcac0fd-e812-4253-9cdc-92d52eaf9f1d" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ReinsuranceVoluntaryReinsuranceDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ReinsuranceVoluntaryReinsuranceDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ReinsuranceVoluntaryReinsuranceDetails" xlink:type="extended" id="i7122cb5b88924d349111233efb7a6b6c_ReinsuranceVoluntaryReinsuranceDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceLineItems_4feea712-b58a-48f3-886e-4cd94e8eb906" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_VoluntaryReinsuranceRecoverableGross_a9776eff-2644-4c23-86d5-9ff58942dca9" xlink:href="cna-20221231.xsd#cna_VoluntaryReinsuranceRecoverableGross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_4feea712-b58a-48f3-886e-4cd94e8eb906" xlink:to="loc_cna_VoluntaryReinsuranceRecoverableGross_a9776eff-2644-4c23-86d5-9ff58942dca9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceTable_f80a6ec3-1f07-4669-9e32-21c25acfc595" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_4feea712-b58a-48f3-886e-4cd94e8eb906" xlink:to="loc_us-gaap_EffectsOfReinsuranceTable_f80a6ec3-1f07-4669-9e32-21c25acfc595" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CreditRatingAxis_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd" xlink:href="cna-20221231.xsd#cna_CreditRatingAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_f80a6ec3-1f07-4669-9e32-21c25acfc595" xlink:to="loc_cna_CreditRatingAxis_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CreditRatingDomain_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd_default" xlink:href="cna-20221231.xsd#cna_CreditRatingDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cna_CreditRatingAxis_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd" xlink:to="loc_cna_CreditRatingDomain_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CreditRatingDomain_79cd97ed-7be4-4e1f-acd1-1bc8049ac532" xlink:href="cna-20221231.xsd#cna_CreditRatingDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cna_CreditRatingAxis_47e328a7-8b18-4bda-8cd8-48dc71ba7dbd" xlink:to="loc_cna_CreditRatingDomain_79cd97ed-7be4-4e1f-acd1-1bc8049ac532" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AMinusToAPlusPlusMember_522a5aa1-a4fe-4969-8cf0-3b11a7d90c15" xlink:href="cna-20221231.xsd#cna_AMinusToAPlusPlusMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_CreditRatingDomain_79cd97ed-7be4-4e1f-acd1-1bc8049ac532" xlink:to="loc_cna_AMinusToAPlusPlusMember_522a5aa1-a4fe-4969-8cf0-3b11a7d90c15" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_BMinusToBPlusPlusMember_8b3c5d73-fb35-41c2-9284-47bf15c4aa32" xlink:href="cna-20221231.xsd#cna_BMinusToBPlusPlusMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_CreditRatingDomain_79cd97ed-7be4-4e1f-acd1-1bc8049ac532" xlink:to="loc_cna_BMinusToBPlusPlusMember_8b3c5d73-fb35-41c2-9284-47bf15c4aa32" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InsolventMember_05068e72-4390-41fb-b3f7-303f8c21b006" xlink:href="cna-20221231.xsd#cna_InsolventMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_CreditRatingDomain_79cd97ed-7be4-4e1f-acd1-1bc8049ac532" xlink:to="loc_cna_InsolventMember_05068e72-4390-41fb-b3f7-303f8c21b006" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ReinsuranceNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ReinsuranceNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ReinsuranceNarrativeDetails" xlink:type="extended" id="i1b368ce6045f4a26aaa0f671b9d990ce_ReinsuranceNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededCreditRiskLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FundsHeldUnderReinsuranceAgreementsLiability_b19f6a06-53ef-4058-9137-79012cee5420" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FundsHeldUnderReinsuranceAgreementsLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:to="loc_us-gaap_FundsHeldUnderReinsuranceAgreementsLiability_b19f6a06-53ef-4058-9137-79012cee5420" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverables_3170d070-fdd1-46b4-8e80-39152baedca9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsuranceRecoverables"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:to="loc_us-gaap_ReinsuranceRecoverables_3170d070-fdd1-46b4-8e80-39152baedca9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DirectAndCededEarnedPremiumsRelatedToBusinessThatIsOneHundredPercentReinsuredAsResultOfSignificantCaptiveProgram_a00b5b80-47bc-4129-887b-30dc81019d12" xlink:href="cna-20221231.xsd#cna_DirectAndCededEarnedPremiumsRelatedToBusinessThatIsOneHundredPercentReinsuredAsResultOfSignificantCaptiveProgram"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:to="loc_cna_DirectAndCededEarnedPremiumsRelatedToBusinessThatIsOneHundredPercentReinsuredAsResultOfSignificantCaptiveProgram_a00b5b80-47bc-4129-887b-30dc81019d12" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded_aeb872d4-ff9e-4e25-b5d4-b21a1696ec63" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:to="loc_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded_aeb872d4-ff9e-4e25-b5d4-b21a1696ec63" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskTable_0ffc525b-de25-4273-b713-eae93e3f1276" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededCreditRiskTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CededCreditRiskLineItems_52d61ac4-3df4-441b-900d-1a7a7a7590a7" xlink:to="loc_us-gaap_CededCreditRiskTable_0ffc525b-de25-4273-b713-eae93e3f1276" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskAxis_b3980fca-cb3d-4496-8a0f-93a73eb58984" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededCreditRiskAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CededCreditRiskTable_0ffc525b-de25-4273-b713-eae93e3f1276" xlink:to="loc_us-gaap_CededCreditRiskAxis_b3980fca-cb3d-4496-8a0f-93a73eb58984" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskReinsurerDomain_b3980fca-cb3d-4496-8a0f-93a73eb58984_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededCreditRiskReinsurerDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CededCreditRiskAxis_b3980fca-cb3d-4496-8a0f-93a73eb58984" xlink:to="loc_us-gaap_CededCreditRiskReinsurerDomain_b3980fca-cb3d-4496-8a0f-93a73eb58984_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededCreditRiskReinsurerDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CededCreditRiskAxis_b3980fca-cb3d-4496-8a0f-93a73eb58984" xlink:to="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SubsidiariesOfBerkshireHathawayGroupMember_9360436e-3225-4c24-bc58-b555e5e801f5" xlink:href="cna-20221231.xsd#cna_SubsidiariesOfBerkshireHathawayGroupMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:to="loc_cna_SubsidiariesOfBerkshireHathawayGroupMember_9360436e-3225-4c24-bc58-b555e5e801f5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CavelloBayReinsuranceLimitedMember_2bb6b89d-317f-475d-a0ae-2d04639c9d69" xlink:href="cna-20221231.xsd#cna_CavelloBayReinsuranceLimitedMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:to="loc_cna_CavelloBayReinsuranceLimitedMember_2bb6b89d-317f-475d-a0ae-2d04639c9d69" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_GatewayRiversInsuranceCompanyMember_292f11fb-32ce-431c-a9bc-d357a6fae9f2" xlink:href="cna-20221231.xsd#cna_GatewayRiversInsuranceCompanyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:to="loc_cna_GatewayRiversInsuranceCompanyMember_292f11fb-32ce-431c-a9bc-d357a6fae9f2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SignificantCaptiveProgramMember_f9289eab-aadb-4f15-8c5f-e95f13a319b2" xlink:href="cna-20221231.xsd#cna_SignificantCaptiveProgramMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CededCreditRiskReinsurerDomain_5f8a2650-b33c-4592-9894-2c0a36eb5818" xlink:to="loc_cna_SignificantCaptiveProgramMember_f9289eab-aadb-4f15-8c5f-e95f13a319b2" xlink:type="arc" order="3"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ReinsuranceComponentsofEarnedPremiumsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ReinsuranceComponentsofEarnedPremiumsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ReinsuranceComponentsofEarnedPremiumsDetails" xlink:type="extended" id="i314cb00df3c3461499aa6f628dfd889e_ReinsuranceComponentsofEarnedPremiumsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceLineItems_5c7ee520-17d9-4bdf-ae56-366c2f6e50ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_5c7ee520-17d9-4bdf-ae56-366c2f6e50ab" xlink:to="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectPremiumsEarned_afd18528-77b2-46a6-a6f4-e549037e9c73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectPremiumsEarned"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:to="loc_us-gaap_DirectPremiumsEarned_afd18528-77b2-46a6-a6f4-e549037e9c73" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssumedPremiumsEarned_210caddf-9b2b-4b9d-bc9b-f1e9a24cdadd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssumedPremiumsEarned"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:to="loc_us-gaap_AssumedPremiumsEarned_210caddf-9b2b-4b9d-bc9b-f1e9a24cdadd" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededPremiumsEarned_201ee948-80f8-446e-bdc7-d9bdb03f2f9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededPremiumsEarned"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:to="loc_us-gaap_CededPremiumsEarned_201ee948-80f8-446e-bdc7-d9bdb03f2f9f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsEarnedNet_883d7f8e-7988-4e78-890b-90fc471860c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsEarnedNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:to="loc_us-gaap_PremiumsEarnedNet_883d7f8e-7988-4e78-890b-90fc471860c2" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsPercentageAssumedToNet_b5d4f825-9861-43d7-b086-da276c88e706" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsPercentageAssumedToNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_c67505e3-71a8-4551-8495-909234e73b73" xlink:to="loc_us-gaap_PremiumsPercentageAssumedToNet_b5d4f825-9861-43d7-b086-da276c88e706" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceTable_3e4769e3-8103-4cc6-be38-d3845e2ac2c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_5c7ee520-17d9-4bdf-ae56-366c2f6e50ab" xlink:to="loc_us-gaap_EffectsOfReinsuranceTable_3e4769e3-8103-4cc6-be38-d3845e2ac2c9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageofassumedpremiumsearnedtonetpremiumsearnedAxis_0a4d18ab-b27f-4faa-9423-6943ddf39a13" xlink:href="cna-20221231.xsd#cna_PercentageofassumedpremiumsearnedtonetpremiumsearnedAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_3e4769e3-8103-4cc6-be38-d3845e2ac2c9" xlink:to="loc_cna_PercentageofassumedpremiumsearnedtonetpremiumsearnedAxis_0a4d18ab-b27f-4faa-9423-6943ddf39a13" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain_0a4d18ab-b27f-4faa-9423-6943ddf39a13_default" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cna_PercentageofassumedpremiumsearnedtonetpremiumsearnedAxis_0a4d18ab-b27f-4faa-9423-6943ddf39a13" xlink:to="loc_cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain_0a4d18ab-b27f-4faa-9423-6943ddf39a13_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain_75002c19-3973-4f50-a581-bdb56611ebd0" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cna_PercentageofassumedpremiumsearnedtonetpremiumsearnedAxis_0a4d18ab-b27f-4faa-9423-6943ddf39a13" xlink:to="loc_cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain_75002c19-3973-4f50-a581-bdb56611ebd0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedPremiumsEarnedToNetPremiumsEarnedMember_e7689cce-ccdd-4c49-8d2b-cef4b703dcf6" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedPremiumsEarnedToNetPremiumsEarnedMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_PercentageOfAssumedEarnedToNetEarnedPremiumsDomain_75002c19-3973-4f50-a581-bdb56611ebd0" xlink:to="loc_cna_PercentageOfAssumedPremiumsEarnedToNetPremiumsEarnedMember_e7689cce-ccdd-4c49-8d2b-cef4b703dcf6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_86d43787-93af-414b-90fa-b2a49855863f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_3e4769e3-8103-4cc6-be38-d3845e2ac2c9" xlink:to="loc_srt_ProductOrServiceAxis_86d43787-93af-414b-90fa-b2a49855863f" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_86d43787-93af-414b-90fa-b2a49855863f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_86d43787-93af-414b-90fa-b2a49855863f" xlink:to="loc_srt_ProductsAndServicesDomain_86d43787-93af-414b-90fa-b2a49855863f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_208c269f-89fe-4ae7-a6df-59cb090f1605" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_86d43787-93af-414b-90fa-b2a49855863f" xlink:to="loc_srt_ProductsAndServicesDomain_208c269f-89fe-4ae7-a6df-59cb090f1605" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_ebd97473-f520-4e12-bbf8-12222a9789ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_208c269f-89fe-4ae7-a6df-59cb090f1605" xlink:to="loc_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_ebd97473-f520-4e12-bbf8-12222a9789ed" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LongtermcareInsuranceProductLineMember_8e9bc6fd-231a-4a13-9115-e8892ed25a7e" xlink:href="cna-20221231.xsd#cna_LongtermcareInsuranceProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_208c269f-89fe-4ae7-a6df-59cb090f1605" xlink:to="loc_cna_LongtermcareInsuranceProductLineMember_8e9bc6fd-231a-4a13-9115-e8892ed25a7e" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ReinsuranceComponentsofWrittenPremiumsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ReinsuranceComponentsofWrittenPremiumsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ReinsuranceComponentsofWrittenPremiumsDetails" xlink:type="extended" id="if5dde402f64d4cf186f2481141c7e6cb_ReinsuranceComponentsofWrittenPremiumsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceLineItems_47673120-8c54-435e-8f7c-763e1dfa778b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsWrittenNetConsolidatedAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_47673120-8c54-435e-8f7c-763e1dfa778b" xlink:to="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectPremiumsWritten_6776bb8c-f7a3-4552-9565-e35ed57ba3ca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectPremiumsWritten"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:to="loc_us-gaap_DirectPremiumsWritten_6776bb8c-f7a3-4552-9565-e35ed57ba3ca" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssumedPremiumsWritten_29c67d54-615d-47a6-a0ad-44fa3d5dc8dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssumedPremiumsWritten"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:to="loc_us-gaap_AssumedPremiumsWritten_29c67d54-615d-47a6-a0ad-44fa3d5dc8dc" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededPremiumsWritten_9a1edc99-9cbc-4fa8-a699-aada7c5a8d94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CededPremiumsWritten"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:to="loc_us-gaap_CededPremiumsWritten_9a1edc99-9cbc-4fa8-a699-aada7c5a8d94" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenNet_79bd9530-032a-4669-adce-8ada8bdb7232" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsWrittenNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:to="loc_us-gaap_PremiumsWrittenNet_79bd9530-032a-4669-adce-8ada8bdb7232" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedPremiumWrittenToPremiumWrittenNet_3df113c7-7df2-47a1-bc0e-eb0a9c868e6f" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedPremiumWrittenToPremiumWrittenNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract_f5d23a27-5054-4efc-9922-4908c74b9f70" xlink:to="loc_cna_PercentageOfAssumedPremiumWrittenToPremiumWrittenNet_3df113c7-7df2-47a1-bc0e-eb0a9c868e6f" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectsOfReinsuranceTable_25e20066-65af-4772-8dad-d621ec32af78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectsOfReinsuranceTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EffectsOfReinsuranceLineItems_47673120-8c54-435e-8f7c-763e1dfa778b" xlink:to="loc_us-gaap_EffectsOfReinsuranceTable_25e20066-65af-4772-8dad-d621ec32af78" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageofassumedpremiumswrittentonetpremiumswrittenAxis_87a4afb6-b49e-48e2-a9a9-5a9b1418354c" xlink:href="cna-20221231.xsd#cna_PercentageofassumedpremiumswrittentonetpremiumswrittenAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_25e20066-65af-4772-8dad-d621ec32af78" xlink:to="loc_cna_PercentageofassumedpremiumswrittentonetpremiumswrittenAxis_87a4afb6-b49e-48e2-a9a9-5a9b1418354c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain_87a4afb6-b49e-48e2-a9a9-5a9b1418354c_default" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_cna_PercentageofassumedpremiumswrittentonetpremiumswrittenAxis_87a4afb6-b49e-48e2-a9a9-5a9b1418354c" xlink:to="loc_cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain_87a4afb6-b49e-48e2-a9a9-5a9b1418354c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain_a207eb6e-b065-4cb1-9cc4-e102b2988aca" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_cna_PercentageofassumedpremiumswrittentonetpremiumswrittenAxis_87a4afb6-b49e-48e2-a9a9-5a9b1418354c" xlink:to="loc_cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain_a207eb6e-b065-4cb1-9cc4-e102b2988aca" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfAssumedPremiumsWrittenToNetPremiumsWrittenMember_88846ea0-2a5b-4937-b7e5-252830a9d0ac" xlink:href="cna-20221231.xsd#cna_PercentageOfAssumedPremiumsWrittenToNetPremiumsWrittenMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_PercentageOfAssumedWrittenToNetWrittenPremiumsDomain_a207eb6e-b065-4cb1-9cc4-e102b2988aca" xlink:to="loc_cna_PercentageOfAssumedPremiumsWrittenToNetPremiumsWrittenMember_88846ea0-2a5b-4937-b7e5-252830a9d0ac" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_17867d48-3905-4401-a6c9-8ba331ea2635" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_EffectsOfReinsuranceTable_25e20066-65af-4772-8dad-d621ec32af78" xlink:to="loc_srt_ProductOrServiceAxis_17867d48-3905-4401-a6c9-8ba331ea2635" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_17867d48-3905-4401-a6c9-8ba331ea2635_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_17867d48-3905-4401-a6c9-8ba331ea2635" xlink:to="loc_srt_ProductsAndServicesDomain_17867d48-3905-4401-a6c9-8ba331ea2635_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5e0bafba-77bd-4c84-b0af-24b0d81610aa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_17867d48-3905-4401-a6c9-8ba331ea2635" xlink:to="loc_srt_ProductsAndServicesDomain_5e0bafba-77bd-4c84-b0af-24b0d81610aa" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_f117872f-5bdb-4480-9e28-81b79c2461cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5e0bafba-77bd-4c84-b0af-24b0d81610aa" xlink:to="loc_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_f117872f-5bdb-4480-9e28-81b79c2461cd" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LongtermcareInsuranceProductLineMember_77ab4306-040f-4832-ab36-379864abf4fb" xlink:href="cna-20221231.xsd#cna_LongtermcareInsuranceProductLineMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5e0bafba-77bd-4c84-b0af-24b0d81610aa" xlink:to="loc_cna_LongtermcareInsuranceProductLineMember_77ab4306-040f-4832-ab36-379864abf4fb" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/DebtScheduleofdebtinstrumentsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#DebtScheduleofdebtinstrumentsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/DebtScheduleofdebtinstrumentsDetails" xlink:type="extended" id="i1147b909714a49249b2d2bc8e5df93b8_DebtScheduleofdebtinstrumentsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a1aa6af8-6957-4c31-bc4c-4410f32d7ce5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a1aa6af8-6957-4c31-bc4c-4410f32d7ce5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_421d8db8-7bab-44dc-bc6d-d06f272258b8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_421d8db8-7bab-44dc-bc6d-d06f272258b8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_85a435e4-aaa8-4871-a06c-c1a12a24d8cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermBorrowings"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_ShortTermBorrowings_85a435e4-aaa8-4871-a06c-c1a12a24d8cc" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_e95533b4-adc9-4efd-ac84-250b4659b811" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_e95533b4-adc9-4efd-ac84-250b4659b811" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_fad249e8-3e32-4360-8a9c-148d6a8cf759" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_DebtLongtermAndShorttermCombinedAmount_fad249e8-3e32-4360-8a9c-148d6a8cf759" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_30e6116a-e5f9-4f1f-bb2b-fb881b397f1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9dd17147-c92d-449d-b276-70f2566f3857" xlink:to="loc_us-gaap_DebtInstrumentTable_30e6116a-e5f9-4f1f-bb2b-fb881b397f1b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_5b257363-f3b5-47d2-9eed-872f10b3fe3f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_30e6116a-e5f9-4f1f-bb2b-fb881b397f1b" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_5b257363-f3b5-47d2-9eed-872f10b3fe3f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_5b257363-f3b5-47d2-9eed-872f10b3fe3f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_5b257363-f3b5-47d2-9eed-872f10b3fe3f" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_5b257363-f3b5-47d2-9eed-872f10b3fe3f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_d265abf5-8475-4607-8de1-6c41741538eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_5b257363-f3b5-47d2-9eed-872f10b3fe3f" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_d265abf5-8475-4607-8de1-6c41741538eb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_13cbe091-db95-4ef7-a276-2af3e1db4601" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubordinatedDebtMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_d265abf5-8475-4607-8de1-6c41741538eb" xlink:to="loc_us-gaap_SubordinatedDebtMember_13cbe091-db95-4ef7-a276-2af3e1db4601" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_11450833-60d5-4e04-8dd8-ed03d10bd2bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_30e6116a-e5f9-4f1f-bb2b-fb881b397f1b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_11450833-60d5-4e04-8dd8-ed03d10bd2bc" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_11450833-60d5-4e04-8dd8-ed03d10bd2bc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_11450833-60d5-4e04-8dd8-ed03d10bd2bc" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_11450833-60d5-4e04-8dd8-ed03d10bd2bc_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_11450833-60d5-4e04-8dd8-ed03d10bd2bc" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes3.950faceamountof550dueMay152024Member_ee9347d9-ba83-40b8-a6b5-7df808f5c6d2" xlink:href="cna-20221231.xsd#cna_SeniorNotes3.950faceamountof550dueMay152024Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_cna_SeniorNotes3.950faceamountof550dueMay152024Member_ee9347d9-ba83-40b8-a6b5-7df808f5c6d2" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes4.500faceamountof500dueMarch12026Member_c451aa0a-fd76-4ab0-8467-0f45c79630f8" xlink:href="cna-20221231.xsd#cna_SeniorNotes4.500faceamountof500dueMarch12026Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_cna_SeniorNotes4.500faceamountof500dueMarch12026Member_c451aa0a-fd76-4ab0-8467-0f45c79630f8" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes3450FaceAmountOf500DueAugust152027Member_8e347cca-e4ae-4070-8497-09c77aaee228" xlink:href="cna-20221231.xsd#cna_SeniorNotes3450FaceAmountOf500DueAugust152027Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_cna_SeniorNotes3450FaceAmountOf500DueAugust152027Member_8e347cca-e4ae-4070-8497-09c77aaee228" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes3.900faceamountof500dueMay12029Member_cd503bad-3ddf-4f6d-b363-14a58f1fe1af" xlink:href="cna-20221231.xsd#cna_SeniorNotes3.900faceamountof500dueMay12029Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_cna_SeniorNotes3.900faceamountof500dueMay12029Member_cd503bad-3ddf-4f6d-b363-14a58f1fe1af" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SeniorNotes2050FaceAmountOf500DueAugust152030Member_18c9346d-649b-40be-a1a3-c56f2d3b4f90" xlink:href="cna-20221231.xsd#cna_SeniorNotes2050FaceAmountOf500DueAugust152030Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_cna_SeniorNotes2050FaceAmountOf500DueAugust152030Member_18c9346d-649b-40be-a1a3-c56f2d3b4f90" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubordinatedDebtMember_89dc4ff5-5ca6-4aae-bab6-fd554e51fc1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubordinatedDebtMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_bec489a7-ea93-4701-9a98-295cca0d913d" xlink:to="loc_us-gaap_SubordinatedDebtMember_89dc4ff5-5ca6-4aae-bab6-fd554e51fc1d" xlink:type="arc" order="5"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansFundedStatusDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansFundedStatusDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansFundedStatusDetails" xlink:type="extended" id="i25f08309cd6f43148992ab95f7fa1328_BenefitPlansFundedStatusDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_afc4ad10-323e-4799-a047-36d36ee52a23" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_afc4ad10-323e-4799-a047-36d36ee52a23" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_5682d006-b3fe-441a-9f4f-469703cb9af7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_5682d006-b3fe-441a-9f4f-469703cb9af7" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_0e317db1-8637-49c7-bf48-799b7d44507d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationContributionsByPlanParticipant_0e317db1-8637-49c7-bf48-799b7d44507d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_48921d76-fea1-4aa2-8765-5c59b2ae9265" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_48921d76-fea1-4aa2-8765-5c59b2ae9265" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_5d81cc54-cafc-44dc-ab76-7aba09b559ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_5d81cc54-cafc-44dc-ab76-7aba09b559ac" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnBenefitObligation_6ebdee01-c3ec-4c53-a459-647a98524f02" xlink:href="cna-20221231.xsd#cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnBenefitObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnBenefitObligation_6ebdee01-c3ec-4c53-a459-647a98524f02" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_39556658-8b71-4780-a219-5839ab47c90b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanSettlementsBenefitObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_9b2757fd-71c2-4f5d-8646-bebbfa8d5b27" xlink:to="loc_us-gaap_DefinedBenefitPlanSettlementsBenefitObligation_39556658-8b71-4780-a219-5839ab47c90b" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_62d30d9b-a465-4ad2-8cd4-3f45d25a0385" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_553acec5-ea60-467c-ba3c-2cf92e95bc72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_553acec5-ea60-467c-ba3c-2cf92e95bc72" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_bf05f1c9-ad3d-46bb-883c-4143fdc6ceb1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_bf05f1c9-ad3d-46bb-883c-4143fdc6ceb1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_03ce0b2c-08d5-4b99-a573-a1300e9cb440" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_03ce0b2c-08d5-4b99-a573-a1300e9cb440" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_fec9b2cc-22ad-4795-a8c0-12e2e1258317" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsContributionsByPlanParticipant_fec9b2cc-22ad-4795-a8c0-12e2e1258317" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_ac10f471-688d-4ab8-b602-cc3f3347de60" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_ac10f471-688d-4ab8-b602-cc3f3347de60" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnPlanAssets_05222079-8002-4610-845f-1bf20da1222d" xlink:href="cna-20221231.xsd#cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_cna_DefinedBenefitPlanForeignCurrencyTranslationAndOtherOnPlanAssets_05222079-8002-4610-845f-1bf20da1222d" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_4ea0ab63-b733-4608-bcd6-f5673155aed9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanSettlementsPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_32d02960-4d56-4bff-9419-9f35466ec8e1" xlink:to="loc_us-gaap_DefinedBenefitPlanSettlementsPlanAssets_4ea0ab63-b733-4608-bcd6-f5673155aed9" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_45da1b0b-dcbe-4306-9f0c-ac19ec40f91c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlanAbstract_f047302d-1cf0-4ce4-92b2-9037fcaa2216" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlanAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlanAbstract_f047302d-1cf0-4ce4-92b2-9037fcaa2216" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_38be85a0-5d1b-4f97-9921-5c2b1b8a788b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlanAbstract_f047302d-1cf0-4ce4-92b2-9037fcaa2216" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_38be85a0-5d1b-4f97-9921-5c2b1b8a788b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_56153fe3-c2a4-4667-8adb-7c39c3e86d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_56153fe3-c2a4-4667-8adb-7c39c3e86d6b" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_87a758eb-7e58-44ed-a090-e12679badc19" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_56153fe3-c2a4-4667-8adb-7c39c3e86d6b" xlink:to="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_87a758eb-7e58-44ed-a090-e12679badc19" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_3177eafb-1abb-415b-a84f-a04ecd653a36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_56153fe3-c2a4-4667-8adb-7c39c3e86d6b" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_3177eafb-1abb-415b-a84f-a04ecd653a36" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_928bc6db-c39c-4896-a881-21671d650205" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheetAbstract_56153fe3-c2a4-4667-8adb-7c39c3e86d6b" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_928bc6db-c39c-4896-a881-21671d650205" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_1186d70d-aa7b-4650-a1ff-3c5165e3aca9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_1186d70d-aa7b-4650-a1ff-3c5165e3aca9" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_c2b13ef3-d20e-476e-9946-f262ee53ddc6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_1186d70d-aa7b-4650-a1ff-3c5165e3aca9" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_c2b13ef3-d20e-476e-9946-f262ee53ddc6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_174c14e2-c1aa-4626-adf6-3587251fe6e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTaxAbstract_1186d70d-aa7b-4650-a1ff-3c5165e3aca9" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax_174c14e2-c1aa-4626-adf6-3587251fe6e6" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d38f4154-dae1-42ae-b0db-07564ee3925e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_64e51b82-7b14-4863-b353-d676ee8596ef" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d38f4154-dae1-42ae-b0db-07564ee3925e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d38f4154-dae1-42ae-b0db-07564ee3925e" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_94b68880-5a29-4ab1-b34f-97587413d9a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d1bf22c5-e3be-4cd1-aea0-bd3e6712dbd4" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_94b68880-5a29-4ab1-b34f-97587413d9a4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_e99ed8ef-ef32-49e3-b770-2585d3db64f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_94b68880-5a29-4ab1-b34f-97587413d9a4" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_e99ed8ef-ef32-49e3-b770-2585d3db64f6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_d255e833-4d22-4d46-9cbd-d9b418b440a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_94b68880-5a29-4ab1-b34f-97587413d9a4" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_d255e833-4d22-4d46-9cbd-d9b418b440a4" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansNarrativeDetails" xlink:type="extended" id="if53ba5787f2c413d827c1df19fbbbf94_BenefitPlansNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_c743b6ee-9503-4eff-8b17-e6368b3e9774" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedBenefitObligation_c743b6ee-9503-4eff-8b17-e6368b3e9774" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_0038c038-eb20-4074-81f5-91134197ab9d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_0038c038-eb20-4074-81f5-91134197ab9d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_a3e32aee-429f-44e3-8ee8-6909da70d408" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation_a3e32aee-429f-44e3-8ee8-6909da70d408" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_3cccfd54-8c82-4b26-9232-1bc785d16ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets_3cccfd54-8c82-4b26-9232-1bc785d16ac6" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Assumptionsusedincalculatingassumedhealthcarecosttrendrate_2e16bac1-0dbc-437c-ae10-c8f350a1402e" xlink:href="cna-20221231.xsd#cna_Assumptionsusedincalculatingassumedhealthcarecosttrendrate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_Assumptionsusedincalculatingassumedhealthcarecosttrendrate_2e16bac1-0dbc-437c-ae10-c8f350a1402e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear_1dbe7bc0-3d8d-4702-b507-0c4db73356d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedNextFiscalYear_1dbe7bc0-3d8d-4702-b507-0c4db73356d4" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_40d546e8-f604-4104-9ed0-ed2097ad8075" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_40d546e8-f604-4104-9ed0-ed2097ad8075" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FutureCapitalCallCommitments_e759c618-ece9-4ac4-a2e0-8f2e16464cec" xlink:href="cna-20221231.xsd#cna_FutureCapitalCallCommitments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_FutureCapitalCallCommitments_e759c618-ece9-4ac4-a2e0-8f2e16464cec" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfLimitedPartnershipsInvestedInPrivateDebtAndEquity_5d1ed4a9-66c2-4953-87f3-bd9ddb9e8076" xlink:href="cna-20221231.xsd#cna_PercentageOfLimitedPartnershipsInvestedInPrivateDebtAndEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_PercentageOfLimitedPartnershipsInvestedInPrivateDebtAndEquity_5d1ed4a9-66c2-4953-87f3-bd9ddb9e8076" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments_a77daa23-b344-4395-bac5-89ab01f636d8" xlink:href="cna-20221231.xsd#cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments_a77daa23-b344-4395-bac5-89ab01f636d8" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_1345ac83-6f1e-4f8a-85cc-1f2856cee6a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear_1345ac83-6f1e-4f8a-85cc-1f2856cee6a7" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_b3feab1a-b302-4163-aa19-b61336c294b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent_b3feab1a-b302-4163-aa19-b61336c294b7" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_e56edf2a-6675-4a55-bd94-5a7d70232c86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_e56edf2a-6675-4a55-bd94-5a7d70232c86" xlink:type="arc" order="12"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_6c8b670a-b2d1-494c-bb94-3479e8040b9e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_6c8b670a-b2d1-494c-bb94-3479e8040b9e" xlink:type="arc" order="13"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CompanyContributionofEligibleCompensationDependingonAgePercent_33b9d3e2-e8aa-4f9e-913e-7d3529d7a26c" xlink:href="cna-20221231.xsd#cna_CompanyContributionofEligibleCompensationDependingonAgePercent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_CompanyContributionofEligibleCompensationDependingonAgePercent_33b9d3e2-e8aa-4f9e-913e-7d3529d7a26c" xlink:type="arc" order="14"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_DefinedContributionPlanEmployersMatchingContributionVestingPeriodinYears_2f5f8f3b-0562-4e22-8d25-2861b5e85d1f" xlink:href="cna-20221231.xsd#cna_DefinedContributionPlanEmployersMatchingContributionVestingPeriodinYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_DefinedContributionPlanEmployersMatchingContributionVestingPeriodinYears_2f5f8f3b-0562-4e22-8d25-2861b5e85d1f" xlink:type="arc" order="15"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_dc2147d6-91f6-40d1-b235-5fb0e50312f1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_dc2147d6-91f6-40d1-b235-5fb0e50312f1" xlink:type="arc" order="16"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ScheduleofDefinedBenefitandContributionPlansDisclosureTable_e65770be-51b7-4304-a4e1-69ee18d99691" xlink:href="cna-20221231.xsd#cna_ScheduleofDefinedBenefitandContributionPlansDisclosureTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_c10f0eef-8dac-43dc-8099-797896f6efd9" xlink:to="loc_cna_ScheduleofDefinedBenefitandContributionPlansDisclosureTable_e65770be-51b7-4304-a4e1-69ee18d99691" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ScheduleofDefinedBenefitandContributionPlansDisclosureTable_e65770be-51b7-4304-a4e1-69ee18d99691" xlink:to="loc_srt_RangeAxis_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0" xlink:to="loc_srt_RangeMember_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dab2505e-62df-4d0c-b4a5-6f459064c114" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1d7ff6ec-e8b8-4344-9a88-7e69a0c74bf0" xlink:to="loc_srt_RangeMember_dab2505e-62df-4d0c-b4a5-6f459064c114" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_3e19d95f-4bb7-4f31-bc3b-b11be16c8659" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dab2505e-62df-4d0c-b4a5-6f459064c114" xlink:to="loc_srt_MinimumMember_3e19d95f-4bb7-4f31-bc3b-b11be16c8659" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_246d8bd5-8532-4a45-993b-ae962df15adb" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dab2505e-62df-4d0c-b4a5-6f459064c114" xlink:to="loc_srt_MaximumMember_246d8bd5-8532-4a45-993b-ae962df15adb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_9f4b073d-5a61-4e01-8183-b11bdada8d91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_cna_ScheduleofDefinedBenefitandContributionPlansDisclosureTable_e65770be-51b7-4304-a4e1-69ee18d99691" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_9f4b073d-5a61-4e01-8183-b11bdada8d91" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9f4b073d-5a61-4e01-8183-b11bdada8d91_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9f4b073d-5a61-4e01-8183-b11bdada8d91" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9f4b073d-5a61-4e01-8183-b11bdada8d91_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_fc496ffb-6afd-48fe-b1fd-69e6f18e876f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9f4b073d-5a61-4e01-8183-b11bdada8d91" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_fc496ffb-6afd-48fe-b1fd-69e6f18e876f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_a51b5163-01ca-41c1-a0ee-22bfa9ff60d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_fc496ffb-6afd-48fe-b1fd-69e6f18e876f" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_a51b5163-01ca-41c1-a0ee-22bfa9ff60d9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_510e07ed-0e4c-43be-ac32-c3995aa73fb9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_fc496ffb-6afd-48fe-b1fd-69e6f18e876f" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_510e07ed-0e4c-43be-ac32-c3995aa73fb9" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansComponentsofNetPeriodicCostBenefitDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansComponentsofNetPeriodicCostBenefitDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansComponentsofNetPeriodicCostBenefitDetails" xlink:type="extended" id="ib369d5c0d32b4d6ab0539b4d48c11af8_BenefitPlansComponentsofNetPeriodicCostBenefitDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_6d1b1424-b62e-4c1a-88a4-811302f687b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_6d1b1424-b62e-4c1a-88a4-811302f687b9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_22860f47-a833-4e40-906e-f729ad67a954" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_22860f47-a833-4e40-906e-f729ad67a954" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_995faf1e-bf79-4890-83ea-34dcd6c69b80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_995faf1e-bf79-4890-83ea-34dcd6c69b80" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_3c9ceb5f-b102-4525-84fb-7991e90c20d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements1_3c9ceb5f-b102-4525-84fb-7991e90c20d3" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_4543689a-fc84-4dbb-9c16-6b94f47a63cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_4543689a-fc84-4dbb-9c16-6b94f47a63cc" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_4e4cd1b6-d737-44fb-a3f0-b5309f8878b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8552f600-d4a5-4a31-8289-70a04ee1d9c5" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_4e4cd1b6-d737-44fb-a3f0-b5309f8878b4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_257e5922-94e8-4b74-b366-e1ef22207481" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_4e4cd1b6-d737-44fb-a3f0-b5309f8878b4" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_257e5922-94e8-4b74-b366-e1ef22207481" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_257e5922-94e8-4b74-b366-e1ef22207481_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_257e5922-94e8-4b74-b366-e1ef22207481" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_257e5922-94e8-4b74-b366-e1ef22207481_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_774d03e6-9ff7-4058-8e8f-d4dfc0baa364" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_257e5922-94e8-4b74-b366-e1ef22207481" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_774d03e6-9ff7-4058-8e8f-d4dfc0baa364" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_7c9343b7-0cca-46a3-8f4d-3acb6c302cd3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_774d03e6-9ff7-4058-8e8f-d4dfc0baa364" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_7c9343b7-0cca-46a3-8f4d-3acb6c302cd3" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansScheduleofNonServiceCostBenefitPresentedintheConsolidatedStatementofOperationsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansScheduleofNonServiceCostBenefitPresentedintheConsolidatedStatementofOperationsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansScheduleofNonServiceCostBenefitPresentedintheConsolidatedStatementofOperationsDetails" xlink:type="extended" id="iea2ee8dc324748009ebe5eb6a77b647b_BenefitPlansScheduleofNonServiceCostBenefitPresentedintheConsolidatedStatementofOperationsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ce407fff-0e4a-43d7-a76e-071518ef6205" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_2f88ac6c-e5c1-4bb6-9633-1bf751c92392" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ce407fff-0e4a-43d7-a76e-071518ef6205" xlink:to="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_2f88ac6c-e5c1-4bb6-9633-1bf751c92392" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_fc317103-1424-4cfb-a5c1-8fa418a02923" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_ce407fff-0e4a-43d7-a76e-071518ef6205" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_fc317103-1424-4cfb-a5c1-8fa418a02923" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_9338ec49-ab53-4be3-83d8-6598d43e06d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_fc317103-1424-4cfb-a5c1-8fa418a02923" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_9338ec49-ab53-4be3-83d8-6598d43e06d3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9338ec49-ab53-4be3-83d8-6598d43e06d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9338ec49-ab53-4be3-83d8-6598d43e06d3" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9338ec49-ab53-4be3-83d8-6598d43e06d3_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_45057f42-f903-4ce1-8caf-4f17df19e160" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9338ec49-ab53-4be3-83d8-6598d43e06d3" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_45057f42-f903-4ce1-8caf-4f17df19e160" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_561e5f5a-16cc-4fca-9986-00c232635a20" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_45057f42-f903-4ce1-8caf-4f17df19e160" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_561e5f5a-16cc-4fca-9986-00c232635a20" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_fc317103-1424-4cfb-a5c1-8fa418a02923" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_dc0ec974-e26d-4c84-8a7c-f96309f44473" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_4d2e4a3b-8615-49f3-9962-e37ab51cb7b6" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_dc0ec974-e26d-4c84-8a7c-f96309f44473" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InsuranceClaimsandPolicyholdersBenefitsIncludingPolicyholdersDividendsMember_43c43d60-43c1-4211-b678-207b04cc7f15" xlink:href="cna-20221231.xsd#cna_InsuranceClaimsandPolicyholdersBenefitsIncludingPolicyholdersDividendsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dc0ec974-e26d-4c84-8a7c-f96309f44473" xlink:to="loc_cna_InsuranceClaimsandPolicyholdersBenefitsIncludingPolicyholdersDividendsMember_43c43d60-43c1-4211-b678-207b04cc7f15" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseMember_ba045a11-3e35-47dc-b293-7ad47d1803ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherOperatingIncomeExpenseMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dc0ec974-e26d-4c84-8a7c-f96309f44473" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseMember_ba045a11-3e35-47dc-b293-7ad47d1803ec" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansActuarialAssumptionsforBenefitObligationsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansActuarialAssumptionsforBenefitObligationsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansActuarialAssumptionsforBenefitObligationsDetails" xlink:type="extended" id="ic230f415b4c14dc087ecbc715f5a3762_BenefitPlansActuarialAssumptionsforBenefitObligationsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4460bb97-3cc3-49ec-9f9d-4c5bc5d808b8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_4aa0612c-8396-44c6-bef8-39e0320e7875" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4460bb97-3cc3-49ec-9f9d-4c5bc5d808b8" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_4aa0612c-8396-44c6-bef8-39e0320e7875" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_87972a05-fb00-42d7-9fa3-1a7c81431795" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4460bb97-3cc3-49ec-9f9d-4c5bc5d808b8" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease_87972a05-fb00-42d7-9fa3-1a7c81431795" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d2733185-7cde-4ea3-82d8-471358a0f13b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4460bb97-3cc3-49ec-9f9d-4c5bc5d808b8" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d2733185-7cde-4ea3-82d8-471358a0f13b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_960b68a2-3c3f-465c-94cf-7f0756323ce5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_d2733185-7cde-4ea3-82d8-471358a0f13b" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_960b68a2-3c3f-465c-94cf-7f0756323ce5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_960b68a2-3c3f-465c-94cf-7f0756323ce5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_960b68a2-3c3f-465c-94cf-7f0756323ce5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_960b68a2-3c3f-465c-94cf-7f0756323ce5_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_a116ac39-bc52-4100-99ac-01ca934c83c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_960b68a2-3c3f-465c-94cf-7f0756323ce5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_a116ac39-bc52-4100-99ac-01ca934c83c3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_34bd32e7-2055-43ec-bd7d-39ec7578edbd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_a116ac39-bc52-4100-99ac-01ca934c83c3" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_34bd32e7-2055-43ec-bd7d-39ec7578edbd" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_761ddd43-9e14-4e40-bfdb-0e4de2fba7bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_a116ac39-bc52-4100-99ac-01ca934c83c3" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_761ddd43-9e14-4e40-bfdb-0e4de2fba7bd" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansActuarialAssumptionsforNetCostorBenefitDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansActuarialAssumptionsforNetCostorBenefitDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansActuarialAssumptionsforNetCostorBenefitDetails" xlink:type="extended" id="i6ac53bc7a3104ed1bb19e42f61661668_BenefitPlansActuarialAssumptionsforNetCostorBenefitDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_86651519-27c0-4bcd-8585-11919b3aa565" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_c31dce51-d289-4de9-980f-172f845f094d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_86651519-27c0-4bcd-8585-11919b3aa565" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_c31dce51-d289-4de9-980f-172f845f094d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_ffcd2f0a-b9ba-4f87-826d-a95b6bd538de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_86651519-27c0-4bcd-8585-11919b3aa565" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_ffcd2f0a-b9ba-4f87-826d-a95b6bd538de" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_5690c338-801a-4eea-9fcf-a936fbc7e184" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_86651519-27c0-4bcd-8585-11919b3aa565" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_5690c338-801a-4eea-9fcf-a936fbc7e184" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7ca95ca1-fa7d-4b49-a173-daeb19bde267" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_86651519-27c0-4bcd-8585-11919b3aa565" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7ca95ca1-fa7d-4b49-a173-daeb19bde267" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_39d1c42f-ce82-4de1-9731-ac788dd7000a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7ca95ca1-fa7d-4b49-a173-daeb19bde267" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_39d1c42f-ce82-4de1-9731-ac788dd7000a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_39d1c42f-ce82-4de1-9731-ac788dd7000a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_39d1c42f-ce82-4de1-9731-ac788dd7000a" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_39d1c42f-ce82-4de1-9731-ac788dd7000a_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_8252d0ae-0805-4fa6-9ba9-62c4f86d6ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_39d1c42f-ce82-4de1-9731-ac788dd7000a" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_8252d0ae-0805-4fa6-9ba9-62c4f86d6ecf" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_65b7e18f-82b8-4041-80b2-35c9d48e14b2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_8252d0ae-0805-4fa6-9ba9-62c4f86d6ecf" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_65b7e18f-82b8-4041-80b2-35c9d48e14b2" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_918ec1cd-4277-4466-aca9-7e230a95744e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_8252d0ae-0805-4fa6-9ba9-62c4f86d6ecf" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_918ec1cd-4277-4466-aca9-7e230a95744e" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansFairValueofPlanAssetsMeasuredonaRecurringBasisDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansFairValueofPlanAssetsMeasuredonaRecurringBasisDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansFairValueofPlanAssetsMeasuredonaRecurringBasisDetails" xlink:type="extended" id="i399c8c76b34d4090ba3141dde3a0bd4b_BenefitPlansFairValueofPlanAssetsMeasuredonaRecurringBasisDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_19777736-88c4-44e8-bc7b-1772368858e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_5df7c5b1-d4fe-4c12-be9f-9a5330797be8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_19777736-88c4-44e8-bc7b-1772368858e5" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_5df7c5b1-d4fe-4c12-be9f-9a5330797be8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_19777736-88c4-44e8-bc7b-1772368858e5" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_079a5016-0b57-4c3e-b8fd-9c99ac59589b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_079a5016-0b57-4c3e-b8fd-9c99ac59589b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_079a5016-0b57-4c3e-b8fd-9c99ac59589b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_079a5016-0b57-4c3e-b8fd-9c99ac59589b" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_079a5016-0b57-4c3e-b8fd-9c99ac59589b_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanAssetCategoriesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_079a5016-0b57-4c3e-b8fd-9c99ac59589b" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedMaturitiesMember_cc58ffa7-c582-423e-a1b8-481def179ddc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FixedMaturitiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:to="loc_us-gaap_FixedMaturitiesMember_cc58ffa7-c582-423e-a1b8-481def179ddc" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_a6dee480-6d6a-451d-a2b9-fa95d0189a09" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FixedMaturitiesMember_cc58ffa7-c582-423e-a1b8-481def179ddc" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_a6dee480-6d6a-451d-a2b9-fa95d0189a09" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_4bbc807c-3f9c-41a9-8da2-bcba66067148" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FixedMaturitiesMember_cc58ffa7-c582-423e-a1b8-481def179ddc" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_4bbc807c-3f9c-41a9-8da2-bcba66067148" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetBackedSecuritiesMember_dfe1c623-2a7e-4edb-8167-ec4b827dfdab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetBackedSecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FixedMaturitiesMember_cc58ffa7-c582-423e-a1b8-481def179ddc" xlink:to="loc_us-gaap_AssetBackedSecuritiesMember_dfe1c623-2a7e-4edb-8167-ec4b827dfdab" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_31947de8-fd6e-4633-b748-e8e3c42707e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_31947de8-fd6e-4633-b748-e8e3c42707e3" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember_1a321707-de3f-42b3-87dc-4eef9a8b348c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:to="loc_us-gaap_ShortTermInvestmentsMember_1a321707-de3f-42b3-87dc-4eef9a8b348c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_1f5a583e-ec01-4606-9038-2807f4b99a03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:to="loc_us-gaap_OtherAssetsMember_1f5a583e-ec01-4606-9038-2807f4b99a03" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanCashMember_a134a0d1-de8f-4999-b3b6-3ef0e813ec14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanCashMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_79f640e2-6463-46a4-88d2-698939584379" xlink:to="loc_us-gaap_DefinedBenefitPlanCashMember_a134a0d1-de8f-4999-b3b6-3ef0e813ec14" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_cac3c0a3-16f9-422b-abc4-2455a70fd0a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_cac3c0a3-16f9-422b-abc4-2455a70fd0a6" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_cac3c0a3-16f9-422b-abc4-2455a70fd0a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_cac3c0a3-16f9-422b-abc4-2455a70fd0a6" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_cac3c0a3-16f9-422b-abc4-2455a70fd0a6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f255e52-6051-4d57-9a11-95b8ecf5fd80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_cac3c0a3-16f9-422b-abc4-2455a70fd0a6" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f255e52-6051-4d57-9a11-95b8ecf5fd80" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel12And3Member_b29354d5-da20-4bca-a9d4-4f7960294fc9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel12And3Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f255e52-6051-4d57-9a11-95b8ecf5fd80" xlink:to="loc_us-gaap_FairValueInputsLevel12And3Member_b29354d5-da20-4bca-a9d4-4f7960294fc9" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_c4bf39be-4fd1-4c37-b4d7-130f70d45460" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInputsLevel12And3Member_b29354d5-da20-4bca-a9d4-4f7960294fc9" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_c4bf39be-4fd1-4c37-b4d7-130f70d45460" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_e8669662-39b9-4c7d-b82a-6d6378ef4b38" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInputsLevel12And3Member_b29354d5-da20-4bca-a9d4-4f7960294fc9" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_e8669662-39b9-4c7d-b82a-6d6378ef4b38" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_31837e03-40c9-4796-a49a-e9bac6941e7e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueInputsLevel12And3Member_b29354d5-da20-4bca-a9d4-4f7960294fc9" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_31837e03-40c9-4796-a49a-e9bac6941e7e" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_73bbc038-fd53-4325-bc29-4d7bf06a06d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f255e52-6051-4d57-9a11-95b8ecf5fd80" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_73bbc038-fd53-4325-bc29-4d7bf06a06d5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_82db134a-5faa-4018-b401-8bf114638cb6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_82db134a-5faa-4018-b401-8bf114638cb6" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_82db134a-5faa-4018-b401-8bf114638cb6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_82db134a-5faa-4018-b401-8bf114638cb6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_82db134a-5faa-4018-b401-8bf114638cb6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_12e994cf-135d-489f-b76a-967336a4de78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_82db134a-5faa-4018-b401-8bf114638cb6" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_12e994cf-135d-489f-b76a-967336a4de78" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_0c04cb0e-643b-4000-a95f-e0fc44662dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_12e994cf-135d-489f-b76a-967336a4de78" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_0c04cb0e-643b-4000-a95f-e0fc44662dd5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_a802b867-f221-4f82-9b28-8f8aa7549cb9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_a802b867-f221-4f82-9b28-8f8aa7549cb9" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_a802b867-f221-4f82-9b28-8f8aa7549cb9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_a802b867-f221-4f82-9b28-8f8aa7549cb9" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_a802b867-f221-4f82-9b28-8f8aa7549cb9_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_d211fa07-1cb0-4891-9550-6a69e28184ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_a802b867-f221-4f82-9b28-8f8aa7549cb9" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_d211fa07-1cb0-4891-9550-6a69e28184ed" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_cd58bedd-44d3-417b-a472-2e4cd038d1ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_d211fa07-1cb0-4891-9550-6a69e28184ed" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_cd58bedd-44d3-417b-a472-2e4cd038d1ac" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_9fad8f9b-190c-4663-b643-4a59915c1a48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_72bf01a2-1877-40c3-9ebd-020368668a7d" xlink:to="loc_us-gaap_InvestmentTypeAxis_9fad8f9b-190c-4663-b643-4a59915c1a48" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_9fad8f9b-190c-4663-b643-4a59915c1a48_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_9fad8f9b-190c-4663-b643-4a59915c1a48" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_9fad8f9b-190c-4663-b643-4a59915c1a48_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_78957ea2-3347-4aa3-a5cc-f797d53854c0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_9fad8f9b-190c-4663-b643-4a59915c1a48" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_78957ea2-3347-4aa3-a5cc-f797d53854c0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember_20ffb216-d1a6-4f35-9b4e-0e1a86354008" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_78957ea2-3347-4aa3-a5cc-f797d53854c0" xlink:to="loc_us-gaap_EquitySecuritiesMember_20ffb216-d1a6-4f35-9b4e-0e1a86354008" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BenefitPlansEstimatedFutureMinimumBenefitPaymentstoParticipantsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BenefitPlansEstimatedFutureMinimumBenefitPaymentstoParticipantsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BenefitPlansEstimatedFutureMinimumBenefitPaymentstoParticipantsDetails" xlink:type="extended" id="i5b3f5a3863c940949c7ffdbe1e334a9d_BenefitPlansEstimatedFutureMinimumBenefitPaymentstoParticipantsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_91941cff-cd91-40a8-99a5-6114a473e053" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_91941cff-cd91-40a8-99a5-6114a473e053" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_63b13749-554c-441b-b229-86587c3c065f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_63b13749-554c-441b-b229-86587c3c065f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_5b78814c-8f88-4b96-90ea-c8f739c46590" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_5b78814c-8f88-4b96-90ea-c8f739c46590" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_07834ff9-1796-448b-b967-758d024eb15a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_07834ff9-1796-448b-b967-758d024eb15a" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_e9528d90-99dc-4ea2-9823-2526fee85eaf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_e9528d90-99dc-4ea2-9823-2526fee85eaf" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_600506f3-feeb-4aa6-a2ef-c0d23b312208" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_600506f3-feeb-4aa6-a2ef-c0d23b312208" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_79a14fad-0676-42f7-96dc-7fb8e52653c3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_4a606c86-15af-4e15-a537-4bb629e9d4ba" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_79a14fad-0676-42f7-96dc-7fb8e52653c3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_79a14fad-0676-42f7-96dc-7fb8e52653c3" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_3431eb6f-d21a-40c2-900f-fdf3d9307f5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetirementPlanTypeDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_9ba23cc2-bda3-44f7-a0e9-4cabb1ab9a92" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_3431eb6f-d21a-40c2-900f-fdf3d9307f5c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_6d18f055-86c7-4c64-98ac-b34794f9edb6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_3431eb6f-d21a-40c2-900f-fdf3d9307f5c" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_6d18f055-86c7-4c64-98ac-b34794f9edb6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_49dd8380-06d6-4106-a4d2-7c60f2dcad37" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_3431eb6f-d21a-40c2-900f-fdf3d9307f5c" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_49dd8380-06d6-4106-a4d2-7c60f2dcad37" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/StockBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#StockBasedCompensationNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/StockBasedCompensationNarrativeDetails" xlink:type="extended" id="i05f1436952764d9088eaf931f1a842fa_StockBasedCompensationNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_7916fb2d-4437-46a2-a131-83ed492199c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_7916fb2d-4437-46a2-a131-83ed492199c8" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_6c87c5e8-be2b-4111-84da-ff61533ab15f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_6c87c5e8-be2b-4111-84da-ff61533ab15f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MeasurementPeriodofSpecificAnnualPerformanceGoalsinYears_a0fe717e-a5b5-4cf7-8917-ea5a79ba8351" xlink:href="cna-20221231.xsd#cna_MeasurementPeriodofSpecificAnnualPerformanceGoalsinYears"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_cna_MeasurementPeriodofSpecificAnnualPerformanceGoalsinYears_a0fe717e-a5b5-4cf7-8917-ea5a79ba8351" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CliffVestingPeriodFollowingDateofGrant_4d823bff-99f2-440c-aa35-1fd8a54a0552" xlink:href="cna-20221231.xsd#cna_CliffVestingPeriodFollowingDateofGrant"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_cna_CliffVestingPeriodFollowingDateofGrant_4d823bff-99f2-440c-aa35-1fd8a54a0552" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_738d9825-27fd-43d4-b834-fed7b73b5f39" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_738d9825-27fd-43d4-b834-fed7b73b5f39" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1a6f3ac3-7a07-4f01-8653-300422cbbbce" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1a6f3ac3-7a07-4f01-8653-300422cbbbce" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_7cadcb00-a1c3-4cc1-81f2-a1b1e31e141e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_7cadcb00-a1c3-4cc1-81f2-a1b1e31e141e" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_3d6f2b7b-7d52-43e8-8f00-7875fdf16a03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_3d6f2b7b-7d52-43e8-8f00-7875fdf16a03" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_439bbff4-da92-4b95-a5fd-3c2bdd450dec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_439bbff4-da92-4b95-a5fd-3c2bdd450dec" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_b73fa756-3990-4144-a2c8-6f4436064228" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_b73fa756-3990-4144-a2c8-6f4436064228" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4f513365-780c-4e69-9c81-4bddab36a88c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_4f513365-780c-4e69-9c81-4bddab36a88c" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_944e6d69-7efe-4cb6-a54f-1abe94c1ad66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_944e6d69-7efe-4cb6-a54f-1abe94c1ad66" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_44e0ce6d-ee6e-4768-ad3d-3ac1188b9ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ae1bc9e7-5df2-4183-bfd3-28aef6a70883" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_44e0ce6d-ee6e-4768-ad3d-3ac1188b9ec6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_cf0cb798-fc18-459a-9c2f-95bc518be0a6" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_44e0ce6d-ee6e-4768-ad3d-3ac1188b9ec6" xlink:to="loc_srt_RangeAxis_cf0cb798-fc18-459a-9c2f-95bc518be0a6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_cf0cb798-fc18-459a-9c2f-95bc518be0a6_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_cf0cb798-fc18-459a-9c2f-95bc518be0a6" xlink:to="loc_srt_RangeMember_cf0cb798-fc18-459a-9c2f-95bc518be0a6_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ada596f7-f305-41ba-a092-59a44aac45d9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_cf0cb798-fc18-459a-9c2f-95bc518be0a6" xlink:to="loc_srt_RangeMember_ada596f7-f305-41ba-a092-59a44aac45d9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_007871e4-5604-487d-b671-6ae9dab6d517" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ada596f7-f305-41ba-a092-59a44aac45d9" xlink:to="loc_srt_MinimumMember_007871e4-5604-487d-b671-6ae9dab6d517" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_338bab2f-c47d-483d-8e9a-07e4f73addd1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ada596f7-f305-41ba-a092-59a44aac45d9" xlink:to="loc_srt_MaximumMember_338bab2f-c47d-483d-8e9a-07e4f73addd1" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/OtherIntangibleAssetsSummaryofOtherIntangibleAssetsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#OtherIntangibleAssetsSummaryofOtherIntangibleAssetsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/OtherIntangibleAssetsSummaryofOtherIntangibleAssetsDetails" xlink:type="extended" id="i298287662d7947968e973fae58f03e12_OtherIntangibleAssetsSummaryofOtherIntangibleAssetsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_f9a87055-a35e-4b39-bb79-7ec8b462c16d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:href="cna-20221231.xsd#cna_ScheduleofOtherIntangibleAssetsAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_f9a87055-a35e-4b39-bb79-7ec8b462c16d" xlink:to="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_ef668640-1a96-4bbe-a2b9-70a07071bfb0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_ef668640-1a96-4bbe-a2b9-70a07071bfb0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_a916fc14-1914-4f3c-951c-327d18409fd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_a916fc14-1914-4f3c-951c-327d18409fd7" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_23568e90-f079-4f4a-a2ac-463ae380f6fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_23568e90-f079-4f4a-a2ac-463ae380f6fb" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_356895bc-29f2-43bd-ba31-6502f1068399" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_356895bc-29f2-43bd-ba31-6502f1068399" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_79c3ff53-87a7-499b-87c4-21c1e0c7a06a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleofOtherIntangibleAssetsAbstract_6789b09d-60bf-4915-9d1d-461d9803f077" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_79c3ff53-87a7-499b-87c4-21c1e0c7a06a" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_cf95b25b-1527-46b2-b7cc-2939654acd5f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_f9a87055-a35e-4b39-bb79-7ec8b462c16d" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_cf95b25b-1527-46b2-b7cc-2939654acd5f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a6a97e68-e8e0-4afe-b15c-da12b517d64d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_cf95b25b-1527-46b2-b7cc-2939654acd5f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a6a97e68-e8e0-4afe-b15c-da12b517d64d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a6a97e68-e8e0-4afe-b15c-da12b517d64d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a6a97e68-e8e0-4afe-b15c-da12b517d64d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a6a97e68-e8e0-4afe-b15c-da12b517d64d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d6f72e12-2125-4780-a6d4-676d90f8c136" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a6a97e68-e8e0-4afe-b15c-da12b517d64d" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d6f72e12-2125-4780-a6d4-676d90f8c136" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeNamesMember_76535d64-e41d-4b54-9b06-46a868ad9408" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TradeNamesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d6f72e12-2125-4780-a6d4-676d90f8c136" xlink:to="loc_us-gaap_TradeNamesMember_76535d64-e41d-4b54-9b06-46a868ad9408" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DistributionRightsMember_a8499ab5-c653-4df2-ba23-66d6a815c086" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DistributionRightsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_d6f72e12-2125-4780-a6d4-676d90f8c136" xlink:to="loc_us-gaap_DistributionRightsMember_a8499ab5-c653-4df2-ba23-66d6a815c086" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ce966d71-d683-4f04-a047-6dee23aeef84" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_cf95b25b-1527-46b2-b7cc-2939654acd5f" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ce966d71-d683-4f04-a047-6dee23aeef84" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ce966d71-d683-4f04-a047-6dee23aeef84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ce966d71-d683-4f04-a047-6dee23aeef84" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ce966d71-d683-4f04-a047-6dee23aeef84_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7ad25926-2a9c-46f4-bd0c-51743f3d8e99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ce966d71-d683-4f04-a047-6dee23aeef84" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7ad25926-2a9c-46f4-bd0c-51743f3d8e99" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LloydsSyndicateCapacityMember_ff589ea1-e9e8-4c29-a77f-2c2501719080" xlink:href="cna-20221231.xsd#cna_LloydsSyndicateCapacityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7ad25926-2a9c-46f4-bd0c-51743f3d8e99" xlink:to="loc_cna_LloydsSyndicateCapacityMember_ff589ea1-e9e8-4c29-a77f-2c2501719080" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AgencyForceMember_33892d12-8329-43b3-ad4a-b7ba9659121a" xlink:href="cna-20221231.xsd#cna_AgencyForceMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7ad25926-2a9c-46f4-bd0c-51743f3d8e99" xlink:to="loc_cna_AgencyForceMember_33892d12-8329-43b3-ad4a-b7ba9659121a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicenseMember_0f2679b2-eaaf-41d4-a6e9-759592f0bed0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LicenseMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7ad25926-2a9c-46f4-bd0c-51743f3d8e99" xlink:to="loc_us-gaap_LicenseMember_0f2679b2-eaaf-41d4-a6e9-759592f0bed0" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/OtherIntangibleAssetsNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#OtherIntangibleAssetsNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/OtherIntangibleAssetsNarrativeDetails" xlink:type="extended" id="i514cfe6fd5e941beac745b94e98f6044_OtherIntangibleAssetsNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_AmortizationExpenseIncludedInOtherOperatingExpenses_4e2c44e0-2c9e-4234-b3b6-70e1ddb3703c" xlink:href="cna-20221231.xsd#cna_AmortizationExpenseIncludedInOtherOperatingExpenses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_cna_AmortizationExpenseIncludedInOtherOperatingExpenses_4e2c44e0-2c9e-4234-b3b6-70e1ddb3703c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_686d1a96-fdb3-448e-bb7f-6001720a81df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_686d1a96-fdb3-448e-bb7f-6001720a81df" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_c10a8f6c-8d37-4677-8aa6-1815ff8ca6b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_c10a8f6c-8d37-4677-8aa6-1815ff8ca6b7" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_0c061e3a-e3dc-474f-8743-7b046422c509" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_0c061e3a-e3dc-474f-8743-7b046422c509" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_a239a572-c4ec-494e-8edd-6f86e7860f88" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_a239a572-c4ec-494e-8edd-6f86e7860f88" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_fe227b0a-b57e-4801-9ced-d400b3eebdab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_fe227b0a-b57e-4801-9ced-d400b3eebdab" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a9b721e3-7c2b-4b01-8c8e-640ecdbf0da7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_de473f3c-68c8-4b09-94fb-219d35956094" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a9b721e3-7c2b-4b01-8c8e-640ecdbf0da7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4aebd3b1-8452-43be-8cde-dcaff544c4d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a9b721e3-7c2b-4b01-8c8e-640ecdbf0da7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4aebd3b1-8452-43be-8cde-dcaff544c4d1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4aebd3b1-8452-43be-8cde-dcaff544c4d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4aebd3b1-8452-43be-8cde-dcaff544c4d1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4aebd3b1-8452-43be-8cde-dcaff544c4d1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_15572d7d-4835-4aac-afa4-e8e1417ba3bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4aebd3b1-8452-43be-8cde-dcaff544c4d1" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_15572d7d-4835-4aac-afa4-e8e1417ba3bc" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_5f169d25-c13b-4dd6-93ad-762e9393352e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIntangibleAssetsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_15572d7d-4835-4aac-afa4-e8e1417ba3bc" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_5f169d25-c13b-4dd6-93ad-762e9393352e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_f0b84a82-8af0-42bb-b5dd-1e038b7446f2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_a9b721e3-7c2b-4b01-8c8e-640ecdbf0da7" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_f0b84a82-8af0-42bb-b5dd-1e038b7446f2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_f0b84a82-8af0-42bb-b5dd-1e038b7446f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f0b84a82-8af0-42bb-b5dd-1e038b7446f2" xlink:to="loc_us-gaap_SegmentDomain_f0b84a82-8af0-42bb-b5dd-1e038b7446f2_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_6b3ee293-1dfd-4fb0-aa02-8c7099a25ef0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_f0b84a82-8af0-42bb-b5dd-1e038b7446f2" xlink:to="loc_us-gaap_SegmentDomain_6b3ee293-1dfd-4fb0-aa02-8c7099a25ef0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_b37dbf74-84a9-4c50-9a0e-afee3599316e" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6b3ee293-1dfd-4fb0-aa02-8c7099a25ef0" xlink:to="loc_cna_InternationalSegmentMember_b37dbf74-84a9-4c50-9a0e-afee3599316e" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/StockholdersEquityandStatutoryAccountingPracticesCombinedstatutorycapitalandsurplusandnetincomelossDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#StockholdersEquityandStatutoryAccountingPracticesCombinedstatutorycapitalandsurplusandnetincomelossDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/StockholdersEquityandStatutoryAccountingPracticesCombinedstatutorycapitalandsurplusandnetincomelossDetails" xlink:type="extended" id="i34e94acbedc5413c8d1dfe0bae6daacb_StockholdersEquityandStatutoryAccountingPracticesCombinedstatutorycapitalandsurplusandnetincomelossDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatutoryAccountingPracticesLineItems_c17fbd09-ec95-437d-a5f4-2403fbfc867a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatutoryAccountingPracticesLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance_3ea700ca-c2b9-4ae8-9e8f-f4d6ba5cdddc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesLineItems_c17fbd09-ec95-437d-a5f4-2403fbfc867a" xlink:to="loc_us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance_3ea700ca-c2b9-4ae8-9e8f-f4d6ba5cdddc" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount_ef467b2b-971e-4412-ac13-569537114492" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatutoryAccountingPracticesLineItems_c17fbd09-ec95-437d-a5f4-2403fbfc867a" xlink:to="loc_us-gaap_StatutoryAccountingPracticesStatutoryNetIncomeAmount_ef467b2b-971e-4412-ac13-569537114492" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatutoryAccountingPracticesTable_3935aaed-cdff-442a-b76e-450df43e9a08" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatutoryAccountingPracticesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatutoryAccountingPracticesLineItems_c17fbd09-ec95-437d-a5f4-2403fbfc867a" xlink:to="loc_us-gaap_StatutoryAccountingPracticesTable_3935aaed-cdff-442a-b76e-450df43e9a08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_813429c5-d6ff-459d-8f63-acc1a6ca2466" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatutoryAccountingPracticesTable_3935aaed-cdff-442a-b76e-450df43e9a08" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_813429c5-d6ff-459d-8f63-acc1a6ca2466" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_813429c5-d6ff-459d-8f63-acc1a6ca2466_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_813429c5-d6ff-459d-8f63-acc1a6ca2466" xlink:to="loc_us-gaap_SegmentDomain_813429c5-d6ff-459d-8f63-acc1a6ca2466_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d09db24d-661b-4e8a-85fc-d4f0d5f9138f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_813429c5-d6ff-459d-8f63-acc1a6ca2466" xlink:to="loc_us-gaap_SegmentDomain_d09db24d-661b-4e8a-85fc-d4f0d5f9138f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CombinedContinentalCasualtyCompaniesMember_3fc87f87-152d-43df-9344-9fea73e061ee" xlink:href="cna-20221231.xsd#cna_CombinedContinentalCasualtyCompaniesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_d09db24d-661b-4e8a-85fc-d4f0d5f9138f" xlink:to="loc_cna_CombinedContinentalCasualtyCompaniesMember_3fc87f87-152d-43df-9344-9fea73e061ee" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/AccumulatedOtherComprehensiveIncomeLossbyComponentScheduleofAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#AccumulatedOtherComprehensiveIncomeLossbyComponentScheduleofAccumulatedOtherComprehensiveIncomeLossbyComponentDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/AccumulatedOtherComprehensiveIncomeLossbyComponentScheduleofAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="extended" id="i727e7e74bd8349b0bbd8aafbccbe9c06_AccumulatedOtherComprehensiveIncomeLossbyComponentScheduleofAccumulatedOtherComprehensiveIncomeLossbyComponentDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0a0c03cd-f790-406e-8521-b3d7fee1a6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0a0c03cd-f790-406e-8521-b3d7fee1a6ae" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_cb111d16-7d6d-4700-9ca1-ff6f94951a90" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:to="loc_us-gaap_StockholdersEquity_cb111d16-7d6d-4700-9ca1-ff6f94951a90" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_afcc71b7-6fbe-4afc-b6c9-b4fae630a544" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:to="loc_us-gaap_OciBeforeReclassificationsNetOfTaxAttributableToParent_afcc71b7-6fbe-4afc-b6c9-b4fae630a544" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_ad70d092-0f94-4ede-84d2-3a6a881c8876" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent_ad70d092-0f94-4ede-84d2-3a6a881c8876" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_d63d8075-7252-47cb-ba7f-eb7b5bf46a14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_ccaa1205-1150-4c26-b90e-d04c240ce3d6" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_d63d8075-7252-47cb-ba7f-eb7b5bf46a14" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_05b41281-cddd-498a-bc3f-7c8f7a363461" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax_d7868068-1dcd-4c5c-b051-4bdac80afefb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReclassificationFromAociCurrentPeriodTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0a0c03cd-f790-406e-8521-b3d7fee1a6ae" xlink:to="loc_us-gaap_ReclassificationFromAociCurrentPeriodTax_d7868068-1dcd-4c5c-b051-4bdac80afefb" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_4255bb8c-03c0-436b-9670-46500fec5d89" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0a0c03cd-f790-406e-8521-b3d7fee1a6ae" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxPortionAttributableToParent1_4255bb8c-03c0-436b-9670-46500fec5d89" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c33d136-cbde-4a0c-bd88-e9a8a87faf63" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_0a0c03cd-f790-406e-8521-b3d7fee1a6ae" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c33d136-cbde-4a0c-bd88-e9a8a87faf63" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_6a0e69a8-e494-4082-a81a-fc5c7eaec22c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c33d136-cbde-4a0c-bd88-e9a8a87faf63" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_6a0e69a8-e494-4082-a81a-fc5c7eaec22c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6a0e69a8-e494-4082-a81a-fc5c7eaec22c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6a0e69a8-e494-4082-a81a-fc5c7eaec22c" xlink:to="loc_us-gaap_EquityComponentDomain_6a0e69a8-e494-4082-a81a-fc5c7eaec22c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_28b205b6-983b-46fa-abbe-a7a4c4a17db7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_6a0e69a8-e494-4082-a81a-fc5c7eaec22c" xlink:to="loc_us-gaap_EquityComponentDomain_28b205b6-983b-46fa-abbe-a7a4c4a17db7" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e98da0ee-59d6-426a-9620-6e77d10bdb69" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_28b205b6-983b-46fa-abbe-a7a4c4a17db7" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e98da0ee-59d6-426a-9620-6e77d10bdb69" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_0ad2b599-f4e9-4b9b-a4c3-aa639138973b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e98da0ee-59d6-426a-9620-6e77d10bdb69" xlink:to="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_0ad2b599-f4e9-4b9b-a4c3-aa639138973b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_bb6ff4b8-d107-44b7-9700-f378c4626e87" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e98da0ee-59d6-426a-9620-6e77d10bdb69" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_bb6ff4b8-d107-44b7-9700-f378c4626e87" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_8462b6ea-851b-44d4-b44f-809b4a3f18ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_e98da0ee-59d6-426a-9620-6e77d10bdb69" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_8462b6ea-851b-44d4-b44f-809b4a3f18ad" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis_fcef742e-8d98-46a7-bd33-3fb365ca2db1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialInstrumentAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_1c33d136-cbde-4a0c-bd88-e9a8a87faf63" xlink:to="loc_us-gaap_FinancialInstrumentAxis_fcef742e-8d98-46a7-bd33-3fb365ca2db1" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fcef742e-8d98-46a7-bd33-3fb365ca2db1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FinancialInstrumentAxis_fcef742e-8d98-46a7-bd33-3fb365ca2db1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_fcef742e-8d98-46a7-bd33-3fb365ca2db1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_86799988-fb37-4939-8dcc-8f2a459b38cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FinancialInstrumentAxis_fcef742e-8d98-46a7-bd33-3fb365ca2db1" xlink:to="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_86799988-fb37-4939-8dcc-8f2a459b38cc" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsMember_bd44d29a-7127-4a5a-80da-f1b739cfa25d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_86799988-fb37-4939-8dcc-8f2a459b38cc" xlink:to="loc_us-gaap_InvestmentsMember_bd44d29a-7127-4a5a-80da-f1b739cfa25d" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInvestmentsMember_8d17cf9f-bf54-4c8b-88b6-d7f25f205410" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherInvestmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_86799988-fb37-4939-8dcc-8f2a459b38cc" xlink:to="loc_us-gaap_OtherInvestmentsMember_8d17cf9f-bf54-4c8b-88b6-d7f25f205410" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BusinessSegmentsNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BusinessSegmentsNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BusinessSegmentsNarrativeDetails" xlink:type="extended" id="iaf6d05ab78384598b4f7719c4a8b4082_BusinessSegmentsNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_bf3c0b29-9a96-4bad-af75-6337ad9d7152" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_9c3e603c-eb74-439c-b49c-5a2568fba0bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfOperatingSegments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_bf3c0b29-9a96-4bad-af75-6337ad9d7152" xlink:to="loc_us-gaap_NumberOfOperatingSegments_9c3e603c-eb74-439c-b49c-5a2568fba0bd" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_Percentageofforeigndirectwrittenpremiums_9974db3d-b38b-4ba0-9e83-c16deaeebf7d" xlink:href="cna-20221231.xsd#cna_Percentageofforeigndirectwrittenpremiums"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_bf3c0b29-9a96-4bad-af75-6337ad9d7152" xlink:to="loc_cna_Percentageofforeigndirectwrittenpremiums_9974db3d-b38b-4ba0-9e83-c16deaeebf7d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_6ca6a60e-89a8-4fa4-9d7f-ae0f43209af2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_bf3c0b29-9a96-4bad-af75-6337ad9d7152" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_6ca6a60e-89a8-4fa4-9d7f-ae0f43209af2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_cf9e2509-0a07-4760-87e0-5a92548dbd54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_6ca6a60e-89a8-4fa4-9d7f-ae0f43209af2" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_cf9e2509-0a07-4760-87e0-5a92548dbd54" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_cf9e2509-0a07-4760-87e0-5a92548dbd54_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_cf9e2509-0a07-4760-87e0-5a92548dbd54" xlink:to="loc_us-gaap_SegmentDomain_cf9e2509-0a07-4760-87e0-5a92548dbd54_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9e0eb081-4e9d-492f-ab58-b9cef4034ba4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_cf9e2509-0a07-4760-87e0-5a92548dbd54" xlink:to="loc_us-gaap_SegmentDomain_9e0eb081-4e9d-492f-ab58-b9cef4034ba4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CoreSegmentsSpecialtyCommercialAndInternationalMember_3d730324-b7ad-4c93-878d-a44b6be4d55a" xlink:href="cna-20221231.xsd#cna_CoreSegmentsSpecialtyCommercialAndInternationalMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9e0eb081-4e9d-492f-ab58-b9cef4034ba4" xlink:to="loc_cna_CoreSegmentsSpecialtyCommercialAndInternationalMember_3d730324-b7ad-4c93-878d-a44b6be4d55a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NonCoreSegmentsLifeGroupNonCoreandCorporateandOtherNonCoreMember_aa5f2fc4-5773-4ace-9d12-8fd1c5942d0e" xlink:href="cna-20221231.xsd#cna_NonCoreSegmentsLifeGroupNonCoreandCorporateandOtherNonCoreMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_9e0eb081-4e9d-492f-ab58-b9cef4034ba4" xlink:to="loc_cna_NonCoreSegmentsLifeGroupNonCoreandCorporateandOtherNonCoreMember_aa5f2fc4-5773-4ace-9d12-8fd1c5942d0e" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BusinessSegmentsIncomeStatementInformationDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BusinessSegmentsIncomeStatementInformationDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BusinessSegmentsIncomeStatementInformationDetails" xlink:type="extended" id="i6da4a8972c1d49ba8a310f75c5da4667_BusinessSegmentsIncomeStatementInformationDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenNet_26e4ae23-4850-4fbd-b8c0-7225519906b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsWrittenNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_PremiumsWrittenNet_26e4ae23-4850-4fbd-b8c0-7225519906b4" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenuesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsEarnedNet_c7c6b7a2-6cca-4775-95f0-4e0f6c13607d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsEarnedNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:to="loc_us-gaap_PremiumsEarnedNet_c7c6b7a2-6cca-4775-95f0-4e0f6c13607d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities_64a31d69-599f-4913-8a77-b3ed8ff36a7b" xlink:href="cna-20221231.xsd#cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:to="loc_cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities_64a31d69-599f-4913-8a77-b3ed8ff36a7b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0d8d110d-bcd6-4725-a823-1c353c8f1183" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_0d8d110d-bcd6-4725-a823-1c353c8f1183" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncome_93052a16-6637-4181-b9cc-641eebc918e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherIncome"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:to="loc_us-gaap_OtherIncome_93052a16-6637-4181-b9cc-641eebc918e0" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OperatingRevenues_332d9545-fd6d-498d-aa4b-717c31fbe3fa" xlink:href="cna-20221231.xsd#cna_OperatingRevenues"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_5eb23e6d-2ab3-43c0-b867-79fe87e66166" xlink:to="loc_cna_OperatingRevenues_332d9545-fd6d-498d-aa4b-717c31fbe3fa" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BenefitsLossesAndExpensesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredNet_15d02e78-99ce-4b28-9dfd-1512efde8443" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PolicyholderBenefitsAndClaimsIncurredNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredNet_15d02e78-99ce-4b28-9dfd-1512efde8443" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PolicyholderDividends_d8f40707-e7b6-4311-881d-dd65dfd0aa39" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PolicyholderDividends"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_us-gaap_PolicyholderDividends_d8f40707-e7b6-4311-881d-dd65dfd0aa39" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_4c3c8b8f-7dbc-4dc7-b54d-dafb024ad11f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_4c3c8b8f-7dbc-4dc7-b54d-dafb024ad11f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CostsFromContractWithCustomers_ffd0b447-233a-46b5-8e18-5905728cca07" xlink:href="cna-20221231.xsd#cna_CostsFromContractWithCustomers"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_cna_CostsFromContractWithCustomers_ffd0b447-233a-46b5-8e18-5905728cca07" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherInsuranceRelatedExpenses_a644ea57-230c-4c76-a601-e20254221f58" xlink:href="cna-20221231.xsd#cna_OtherInsuranceRelatedExpenses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_cna_OtherInsuranceRelatedExpenses_a644ea57-230c-4c76-a601-e20254221f58" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherExpenses_f030d1d4-8399-4827-b017-05c212d11d36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherExpenses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_us-gaap_OtherExpenses_f030d1d4-8399-4827-b017-05c212d11d36" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BenefitsLossesAndExpenses_13e327da-0242-4a88-a3cc-f6875e4d2eeb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BenefitsLossesAndExpenses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_990e36ad-1af2-4600-9047-91da572626f8" xlink:to="loc_us-gaap_BenefitsLossesAndExpenses_13e327da-0242-4a88-a3cc-f6875e4d2eeb" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax_fcacd143-f36b-44b6-bf29-b4e3e60e442f" xlink:href="cna-20221231.xsd#cna_OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_cna_OperatingIncomeLossFromContinuingOperationsBeforeIncomeTax_fcacd143-f36b-44b6-bf29-b4e3e60e442f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncomeTaxExpenseBenefitOnOperatingIncomeLoss_96d5ab05-c868-4f7f-88e7-9dfbdb231a97" xlink:href="cna-20221231.xsd#cna_IncomeTaxExpenseBenefitOnOperatingIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_cna_IncomeTaxExpenseBenefitOnOperatingIncomeLoss_96d5ab05-c868-4f7f-88e7-9dfbdb231a97" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent_56e9cf53-afe0-4e65-ab61-b6bead54859e" xlink:href="cna-20221231.xsd#cna_NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_cna_NetOperatingIncomeLossFromContinuingOperationsAttributabletoParent_56e9cf53-afe0-4e65-ab61-b6bead54859e" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesRealizedGainLoss_93b13b4b-de17-40ac-a6fc-b0bf90e29078" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_DebtSecuritiesRealizedGainLoss_93b13b4b-de17-40ac-a6fc-b0bf90e29078" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses_84ebadaa-6e06-43a1-8825-8f7edc923e47" xlink:href="cna-20221231.xsd#cna_IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_cna_IncomeTaxExpenseBenefitOnNetRealizedInvestmentGainsLosses_84ebadaa-6e06-43a1-8825-8f7edc923e47" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetRealizedInvestmentGainsLosses_17e1ea89-761d-4be0-adf0-550caa27bec6" xlink:href="cna-20221231.xsd#cna_NetRealizedInvestmentGainsLosses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_cna_NetRealizedInvestmentGainsLosses_17e1ea89-761d-4be0-adf0-550caa27bec6" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperations_cb20fcab-7d54-46d8-9cc9-ce7f117bef7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromContinuingOperations"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperations_cb20fcab-7d54-46d8-9cc9-ce7f117bef7b" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5036ac01-4059-4fd2-91ee-03cbe9c62dc0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e334b265-e043-4b2c-8975-239c5dc84924" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5036ac01-4059-4fd2-91ee-03cbe9c62dc0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5036ac01-4059-4fd2-91ee-03cbe9c62dc0" xlink:to="loc_srt_ConsolidationItemsAxis_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9" xlink:to="loc_srt_ConsolidationItemsDomain_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_9404bdb1-73d7-4964-b0fe-2b38a278209f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_8b9e79f7-8fb8-4766-8f6c-cd0f7d3e3cd9" xlink:to="loc_srt_ConsolidationItemsDomain_9404bdb1-73d7-4964-b0fe-2b38a278209f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_248efbe2-0ca1-491c-ab58-95ae0104f387" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingSegmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_9404bdb1-73d7-4964-b0fe-2b38a278209f" xlink:to="loc_us-gaap_OperatingSegmentsMember_248efbe2-0ca1-491c-ab58-95ae0104f387" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_b2deb801-c006-46a0-b9da-39f1767324ad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntersegmentEliminationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_9404bdb1-73d7-4964-b0fe-2b38a278209f" xlink:to="loc_us-gaap_IntersegmentEliminationMember_b2deb801-c006-46a0-b9da-39f1767324ad" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_a21bad87-26cb-4939-856c-77b2e0f8d61d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_5036ac01-4059-4fd2-91ee-03cbe9c62dc0" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_a21bad87-26cb-4939-856c-77b2e0f8d61d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a21bad87-26cb-4939-856c-77b2e0f8d61d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a21bad87-26cb-4939-856c-77b2e0f8d61d" xlink:to="loc_us-gaap_SegmentDomain_a21bad87-26cb-4939-856c-77b2e0f8d61d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_a21bad87-26cb-4939-856c-77b2e0f8d61d" xlink:to="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_d7a81e7e-cb21-4398-b21e-ff138ce0f35a" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:to="loc_cna_SpecialtySegmentMember_d7a81e7e-cb21-4398-b21e-ff138ce0f35a" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_24866300-da61-4b0a-9d61-a3c8b43e0856" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:to="loc_cna_CommercialSegmentMember_24866300-da61-4b0a-9d61-a3c8b43e0856" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_729adc26-0b79-4085-9fb9-8fc8e12c809b" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:to="loc_cna_InternationalSegmentMember_729adc26-0b79-4085-9fb9-8fc8e12c809b" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LifeAndGroupNonCoreSegmentMember_a4c18868-3146-4b0c-905e-2a3f5f844b0d" xlink:href="cna-20221231.xsd#cna_LifeAndGroupNonCoreSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:to="loc_cna_LifeAndGroupNonCoreSegmentMember_a4c18868-3146-4b0c-905e-2a3f5f844b0d" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_b8322732-6e50-4278-bfe4-131156f6ccd0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_59c6429e-2076-4fd2-91ae-403daa294c9b" xlink:to="loc_us-gaap_CorporateAndOtherMember_b8322732-6e50-4278-bfe4-131156f6ccd0" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BusinessSegmentsBalanceSheetInformationDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BusinessSegmentsBalanceSheetInformationDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BusinessSegmentsBalanceSheetInformationDetails" xlink:type="extended" id="iba8eb5fbbcc04b7cb401e022078cc73d_BusinessSegmentsBalanceSheetInformationDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentReportingInformationLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesGross_062b136a-0e65-41a7-9b31-889f983a70b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReinsuranceRecoverablesGross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_ReinsuranceRecoverablesGross_062b136a-0e65-41a7-9b31-889f983a70b0" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsReceivableGross_7957d025-217f-4702-bfd7-27bcf019aca4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PremiumsReceivableGross"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_PremiumsReceivableGross_7957d025-217f-4702-bfd7-27bcf019aca4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCosts_d409c98b-8a93-41dd-a98f-2d9559ecdbaf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredPolicyAcquisitionCosts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_DeferredPolicyAcquisitionCosts_d409c98b-8a93-41dd-a98f-2d9559ecdbaf" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_9a923a13-af4e-4167-b96f-65f945f6f188" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Goodwill"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_Goodwill_9a923a13-af4e-4167-b96f-65f945f6f188" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_d29c34ce-64f9-4233-b2b0-0ca4d32ed26d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerAssetNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_d29c34ce-64f9-4233-b2b0-0ca4d32ed26d" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceLossReservesAbstract_1afed310-a26d-49d0-aa1e-f90199b88955" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InsuranceLossReservesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_InsuranceLossReservesAbstract_1afed310-a26d-49d0-aa1e-f90199b88955" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_0ad10fd0-2054-41c1-b53c-3a2752869750" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceLossReservesAbstract_1afed310-a26d-49d0-aa1e-f90199b88955" xlink:to="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_0ad10fd0-2054-41c1-b53c-3a2752869750" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnearnedPremiums_9370ad4a-5b97-4cfb-8e2b-bacbdca8c84d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnearnedPremiums"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceLossReservesAbstract_1afed310-a26d-49d0-aa1e-f90199b88955" xlink:to="loc_us-gaap_UnearnedPremiums_9370ad4a-5b97-4cfb-8e2b-bacbdca8c84d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForFuturePolicyBenefits_f41baf24-4170-45d2-96e3-525671a974e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilityForFuturePolicyBenefits"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InsuranceLossReservesAbstract_1afed310-a26d-49d0-aa1e-f90199b88955" xlink:to="loc_us-gaap_LiabilityForFuturePolicyBenefits_f41baf24-4170-45d2-96e3-525671a974e6" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_ca5268fb-1955-400a-bdcd-9e4fe3bda3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_ContractWithCustomerLiability_ca5268fb-1955-400a-bdcd-9e4fe3bda3d9" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a9073410-ee40-4ca3-b0a4-185dac7c313d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_0ab569aa-a81b-418e-b48f-40a76916d37d" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a9073410-ee40-4ca3-b0a4-185dac7c313d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_9b44e101-28b7-4455-a7b2-94913bb75193" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a9073410-ee40-4ca3-b0a4-185dac7c313d" xlink:to="loc_srt_ConsolidationItemsAxis_9b44e101-28b7-4455-a7b2-94913bb75193" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_9b44e101-28b7-4455-a7b2-94913bb75193_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_9b44e101-28b7-4455-a7b2-94913bb75193" xlink:to="loc_srt_ConsolidationItemsDomain_9b44e101-28b7-4455-a7b2-94913bb75193_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_0d2995cf-6374-478a-b28e-07b60590eb92" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_9b44e101-28b7-4455-a7b2-94913bb75193" xlink:to="loc_srt_ConsolidationItemsDomain_0d2995cf-6374-478a-b28e-07b60590eb92" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_37938fec-66df-4c20-943a-dd5a3a77cc7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingSegmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_0d2995cf-6374-478a-b28e-07b60590eb92" xlink:to="loc_us-gaap_OperatingSegmentsMember_37938fec-66df-4c20-943a-dd5a3a77cc7f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_d0d75890-b290-4c48-9a40-cfff7e0b582a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntersegmentEliminationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_0d2995cf-6374-478a-b28e-07b60590eb92" xlink:to="loc_us-gaap_IntersegmentEliminationMember_d0d75890-b290-4c48-9a40-cfff7e0b582a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d88f0653-4ec2-4b4c-959f-4335f9b6207a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_a9073410-ee40-4ca3-b0a4-185dac7c313d" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d88f0653-4ec2-4b4c-959f-4335f9b6207a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d88f0653-4ec2-4b4c-959f-4335f9b6207a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d88f0653-4ec2-4b4c-959f-4335f9b6207a" xlink:to="loc_us-gaap_SegmentDomain_d88f0653-4ec2-4b4c-959f-4335f9b6207a_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d88f0653-4ec2-4b4c-959f-4335f9b6207a" xlink:to="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_fc4d9a83-9f51-4941-83bf-34b848483712" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:to="loc_cna_SpecialtySegmentMember_fc4d9a83-9f51-4941-83bf-34b848483712" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_1c730b6e-2d61-4c17-b111-5f0c4e70f971" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:to="loc_cna_CommercialSegmentMember_1c730b6e-2d61-4c17-b111-5f0c4e70f971" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_486d7ce2-df81-4c34-91d6-1598528cadef" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:to="loc_cna_InternationalSegmentMember_486d7ce2-df81-4c34-91d6-1598528cadef" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LifeAndGroupNonCoreSegmentMember_9ea91e57-e95d-42fc-88be-0a3a33ea8c03" xlink:href="cna-20221231.xsd#cna_LifeAndGroupNonCoreSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:to="loc_cna_LifeAndGroupNonCoreSegmentMember_9ea91e57-e95d-42fc-88be-0a3a33ea8c03" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_fdfe318a-4db9-49a2-bf49-55695a877c71" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_63fd4c1a-b041-4c6b-a7ec-7aba7bc84d30" xlink:to="loc_us-gaap_CorporateAndOtherMember_fdfe318a-4db9-49a2-bf49-55695a877c71" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/BusinessSegmentsRevenuesbyLineofBusinessDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#BusinessSegmentsRevenuesbyLineofBusinessDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/BusinessSegmentsRevenuesbyLineofBusinessDetails" xlink:type="extended" id="i9229b1e22ecb47e2a328e62c13d2efba_BusinessSegmentsRevenuesbyLineofBusinessDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_d5643b7f-c7db-4094-ae4e-0b7170164812" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_4d1eae47-52d4-4b70-a903-8f399fe2162b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Revenues"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d5643b7f-c7db-4094-ae4e-0b7170164812" xlink:to="loc_us-gaap_Revenues_4d1eae47-52d4-4b70-a903-8f399fe2162b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss_7255a31c-36b1-484a-bdc6-5fdfeba5e4e5" xlink:href="cna-20221231.xsd#cna_RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d5643b7f-c7db-4094-ae4e-0b7170164812" xlink:to="loc_cna_RevenuesExcludingInvestmentsAndDerivativesRealizedGainLoss_7255a31c-36b1-484a-bdc6-5fdfeba5e4e5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentsandDerivativesRealizedGainLoss_854e3183-472f-4989-9578-7caebe88692e" xlink:href="cna-20221231.xsd#cna_InvestmentsandDerivativesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_d5643b7f-c7db-4094-ae4e-0b7170164812" xlink:to="loc_cna_InvestmentsandDerivativesRealizedGainLoss_854e3183-472f-4989-9578-7caebe88692e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_ba29ba10-0fb9-43df-8248-57604ad17865" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_d5643b7f-c7db-4094-ae4e-0b7170164812" xlink:to="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_ba29ba10-0fb9-43df-8248-57604ad17865" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_2f11202d-f86e-4724-8334-140001d41cb1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_ba29ba10-0fb9-43df-8248-57604ad17865" xlink:to="loc_srt_ProductOrServiceAxis_2f11202d-f86e-4724-8334-140001d41cb1" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_2f11202d-f86e-4724-8334-140001d41cb1_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_2f11202d-f86e-4724-8334-140001d41cb1" xlink:to="loc_srt_ProductsAndServicesDomain_2f11202d-f86e-4724-8334-140001d41cb1_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_2f11202d-f86e-4724-8334-140001d41cb1" xlink:to="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ManagementandProfessionalLiabilityMember_c496cd9e-5a4c-4cd3-92df-2f4bc894892b" xlink:href="cna-20221231.xsd#cna_ManagementandProfessionalLiabilityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_ManagementandProfessionalLiabilityMember_c496cd9e-5a4c-4cd3-92df-2f4bc894892b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SuretyMember_735d78c4-88b0-4272-beb4-c6194cef485a" xlink:href="cna-20221231.xsd#cna_SuretyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_SuretyMember_735d78c4-88b0-4272-beb4-c6194cef485a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_WarrantyAlternativeRisksMember_bbb2585c-a36a-455e-80a2-5acdb5608b92" xlink:href="cna-20221231.xsd#cna_WarrantyAlternativeRisksMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_WarrantyAlternativeRisksMember_bbb2585c-a36a-455e-80a2-5acdb5608b92" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_MiddleMarketsMember_ead02d57-3c3e-4f75-b8c6-33ad0d870f63" xlink:href="cna-20221231.xsd#cna_MiddleMarketsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_MiddleMarketsMember_ead02d57-3c3e-4f75-b8c6-33ad0d870f63" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionMember_7ea1b7fc-b704-4368-9690-796543ff4223" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConstructionMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_us-gaap_ConstructionMember_7ea1b7fc-b704-4368-9690-796543ff4223" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SmallBusinessMember_0807f55c-d6b5-4477-890d-fda24e1c40fb" xlink:href="cna-20221231.xsd#cna_SmallBusinessMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_SmallBusinessMember_0807f55c-d6b5-4477-890d-fda24e1c40fb" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_OtherCommercialInsuranceMember_3a3e1c63-780e-46e3-9611-c479646c17af" xlink:href="cna-20221231.xsd#cna_OtherCommercialInsuranceMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_OtherCommercialInsuranceMember_3a3e1c63-780e-46e3-9611-c479646c17af" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CNACanadaMember_085adeb3-a5aa-41a3-8391-e97a1833ce93" xlink:href="cna-20221231.xsd#cna_CNACanadaMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_CNACanadaMember_085adeb3-a5aa-41a3-8391-e97a1833ce93" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CNAEuropeMember_f15735e0-34b6-4052-9c01-e6045e7464f0" xlink:href="cna-20221231.xsd#cna_CNAEuropeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_CNAEuropeMember_f15735e0-34b6-4052-9c01-e6045e7464f0" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_HardyMember_f1929783-feec-4fb8-97bf-bd4d52322f0b" xlink:href="cna-20221231.xsd#cna_HardyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_83a398be-fab8-454e-9faf-34282461b24d" xlink:to="loc_cna_HardyMember_f1929783-feec-4fb8-97bf-bd4d52322f0b" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_60003013-da2d-4d04-abe7-e90ab8454534" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_ba29ba10-0fb9-43df-8248-57604ad17865" xlink:to="loc_srt_ConsolidationItemsAxis_60003013-da2d-4d04-abe7-e90ab8454534" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_60003013-da2d-4d04-abe7-e90ab8454534_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_60003013-da2d-4d04-abe7-e90ab8454534" xlink:to="loc_srt_ConsolidationItemsDomain_60003013-da2d-4d04-abe7-e90ab8454534_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_5fd234cc-c25d-46e1-a361-105a7bc273a0" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidationItemsDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_60003013-da2d-4d04-abe7-e90ab8454534" xlink:to="loc_srt_ConsolidationItemsDomain_5fd234cc-c25d-46e1-a361-105a7bc273a0" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_8fc953e1-4d21-4302-812c-686505ea07fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingSegmentsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_5fd234cc-c25d-46e1-a361-105a7bc273a0" xlink:to="loc_us-gaap_OperatingSegmentsMember_8fc953e1-4d21-4302-812c-686505ea07fb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_3c37f603-4499-4e67-9d8d-73db38c43e03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IntersegmentEliminationMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_5fd234cc-c25d-46e1-a361-105a7bc273a0" xlink:to="loc_us-gaap_IntersegmentEliminationMember_3c37f603-4499-4e67-9d8d-73db38c43e03" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_27d6ae01-55bf-4dd0-af91-827483ef59f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementBusinessSegmentsAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTable_ba29ba10-0fb9-43df-8248-57604ad17865" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_27d6ae01-55bf-4dd0-af91-827483ef59f7" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_27d6ae01-55bf-4dd0-af91-827483ef59f7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_27d6ae01-55bf-4dd0-af91-827483ef59f7" xlink:to="loc_us-gaap_SegmentDomain_27d6ae01-55bf-4dd0-af91-827483ef59f7_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SegmentDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_27d6ae01-55bf-4dd0-af91-827483ef59f7" xlink:to="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_SpecialtySegmentMember_1ec12fd7-c52d-42ae-be81-c5d8fa1f4feb" xlink:href="cna-20221231.xsd#cna_SpecialtySegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:to="loc_cna_SpecialtySegmentMember_1ec12fd7-c52d-42ae-be81-c5d8fa1f4feb" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CommercialSegmentMember_2cd63303-366a-410f-bd4b-c71b008aed12" xlink:href="cna-20221231.xsd#cna_CommercialSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:to="loc_cna_CommercialSegmentMember_2cd63303-366a-410f-bd4b-c71b008aed12" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InternationalSegmentMember_eec6fe38-2490-4e7c-b9a8-7688204ba3f0" xlink:href="cna-20221231.xsd#cna_InternationalSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:to="loc_cna_InternationalSegmentMember_eec6fe38-2490-4e7c-b9a8-7688204ba3f0" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LifeAndGroupNonCoreSegmentMember_3059b678-165c-4966-a8bc-b5d909f7e9bd" xlink:href="cna-20221231.xsd#cna_LifeAndGroupNonCoreSegmentMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:to="loc_cna_LifeAndGroupNonCoreSegmentMember_3059b678-165c-4966-a8bc-b5d909f7e9bd" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_53250093-1cc1-4071-a875-fbc4c6312485" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateAndOtherMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_0133f093-d1ba-445c-a925-d87d7cc3e818" xlink:to="loc_us-gaap_CorporateAndOtherMember_53250093-1cc1-4071-a875-fbc4c6312485" xlink:type="arc" order="4"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#RelatedPartyTransactionsNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/RelatedPartyTransactionsNarrativeDetails" xlink:type="extended" id="i568fd145dc2a4f17a4fadd4e84e9577d_RelatedPartyTransactionsNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_aa70ec21-f8de-4e4a-8910-f74d58fd8d31" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:to="loc_us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty_aa70ec21-f8de-4e4a-8910-f74d58fd8d31" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent_28c37b9e-9656-40c6-9322-a742f3d027cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DueToRelatedPartiesCurrentAndNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:to="loc_us-gaap_DueToRelatedPartiesCurrentAndNoncurrent_28c37b9e-9656-40c6-9322-a742f3d027cd" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueFromRelatedParties_e7c17beb-8df9-4b3e-ac99-28b460eb7660" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DueFromRelatedParties"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:to="loc_us-gaap_DueFromRelatedParties_e7c17beb-8df9-4b3e-ac99-28b460eb7660" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromRelatedParties_ea79f0bd-a48e-49bd-96b3-94683719b0cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromRelatedParties"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:to="loc_us-gaap_RevenueFromRelatedParties_ea79f0bd-a48e-49bd-96b3-94683719b0cb" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_45d0e5fc-b1c2-4831-bb10-81fe1a45f7e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9f75eb97-bffe-4602-bff2-0654a5c2e403" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_45d0e5fc-b1c2-4831-bb10-81fe1a45f7e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0195b31a-2cb9-4cc3-b124-ec22c08e7d90" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_45d0e5fc-b1c2-4831-bb10-81fe1a45f7e5" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0195b31a-2cb9-4cc3-b124-ec22c08e7d90" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_0195b31a-2cb9-4cc3-b124-ec22c08e7d90_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0195b31a-2cb9-4cc3-b124-ec22c08e7d90" xlink:to="loc_us-gaap_RelatedPartyDomain_0195b31a-2cb9-4cc3-b124-ec22c08e7d90_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_89fe4945-91f5-4d16-943c-21f2fedb2560" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_0195b31a-2cb9-4cc3-b124-ec22c08e7d90" xlink:to="loc_us-gaap_RelatedPartyDomain_89fe4945-91f5-4d16-943c-21f2fedb2560" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_FeesandexpensesofinvestmentfacilitiesandservicesMember_4678745a-5d7e-48c9-bcc0-218ad20c53db" xlink:href="cna-20221231.xsd#cna_FeesandexpensesofinvestmentfacilitiesandservicesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_89fe4945-91f5-4d16-943c-21f2fedb2560" xlink:to="loc_cna_FeesandexpensesofinvestmentfacilitiesandservicesMember_4678745a-5d7e-48c9-bcc0-218ad20c53db" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CorporateServicesandRelatedTravelExpensesMember_df8526bb-64f5-4191-a1f7-a27b51c5838d" xlink:href="cna-20221231.xsd#cna_CorporateServicesandRelatedTravelExpensesMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_89fe4945-91f5-4d16-943c-21f2fedb2560" xlink:to="loc_cna_CorporateServicesandRelatedTravelExpensesMember_df8526bb-64f5-4191-a1f7-a27b51c5838d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MajorityShareholderMember_425a7269-2702-4faf-a492-f41695208431" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MajorityShareholderMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_89fe4945-91f5-4d16-943c-21f2fedb2560" xlink:to="loc_us-gaap_MajorityShareholderMember_425a7269-2702-4faf-a492-f41695208431" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#NonInsuranceRevenuesfromContractswithCustomersNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersNarrativeDetails" xlink:type="extended" id="i19ed3265ba0e493b8af3250f6b233e44_NonInsuranceRevenuesfromContractswithCustomersNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_cb22bab9-1562-415b-b588-bde6ea1b504b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiability"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:to="loc_us-gaap_ContractWithCustomerLiability_cb22bab9-1562-415b-b588-bde6ea1b504b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_5a991e33-2602-4247-a202-1cae8c7d35ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_5a991e33-2602-4247-a202-1cae8c7d35ea" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_1640ef95-040c-4a04-ac7f-39ef2941db22" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerAssetNet"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_1640ef95-040c-4a04-ac7f-39ef2941db22" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfDeferredSalesCommissions_0c0470e8-d504-4a6a-bd2b-4451a0cec238" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AmortizationOfDeferredSalesCommissions"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:to="loc_us-gaap_AmortizationOfDeferredSalesCommissions_0c0470e8-d504-4a6a-bd2b-4451a0cec238" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c11da99e-32bd-42e5-83f0-9fd5c48d01df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_a11e02e9-6cb2-46bb-8676-e759f3dec4ba" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c11da99e-32bd-42e5-83f0-9fd5c48d01df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostAxis_531da348-6d65-43ea-b115-4db46d21f04e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CapitalizedContractCostAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_c11da99e-32bd-42e5-83f0-9fd5c48d01df" xlink:to="loc_us-gaap_CapitalizedContractCostAxis_531da348-6d65-43ea-b115-4db46d21f04e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_531da348-6d65-43ea-b115-4db46d21f04e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CapitalizedContractCostDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_531da348-6d65-43ea-b115-4db46d21f04e" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_531da348-6d65-43ea-b115-4db46d21f04e_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostDomain_c0a2f054-ad9a-4745-af6b-f7a841c68878" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CapitalizedContractCostDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CapitalizedContractCostAxis_531da348-6d65-43ea-b115-4db46d21f04e" xlink:to="loc_us-gaap_CapitalizedContractCostDomain_c0a2f054-ad9a-4745-af6b-f7a841c68878" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CapitalizedCommissionCostsMember_f5026de1-0cdc-4b63-9555-a6c4640c35a5" xlink:href="cna-20221231.xsd#cna_CapitalizedCommissionCostsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_c0a2f054-ad9a-4745-af6b-f7a841c68878" xlink:to="loc_cna_CapitalizedCommissionCostsMember_f5026de1-0cdc-4b63-9555-a6c4640c35a5" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CapitalizedAdministratorServiceCostsMember_43e77a9f-18f4-43a8-94ea-d9635313ea3a" xlink:href="cna-20221231.xsd#cna_CapitalizedAdministratorServiceCostsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostDomain_c0a2f054-ad9a-4745-af6b-f7a841c68878" xlink:to="loc_cna_CapitalizedAdministratorServiceCostsMember_43e77a9f-18f4-43a8-94ea-d9635313ea3a" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails" xlink:type="extended" id="i045de9b01fa540bea893e4c9949b6f66_NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_eb66704b-9749-470f-94cd-89894e641115" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_c5461059-e68f-4b3a-b288-ad6ae40e5e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_eb66704b-9749-470f-94cd-89894e641115" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_c5461059-e68f-4b3a-b288-ad6ae40e5e7b" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_4af63bcd-b6ae-4418-a320-168c17b7466a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_eb66704b-9749-470f-94cd-89894e641115" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_4af63bcd-b6ae-4418-a320-168c17b7466a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f6bc0fab-a1b5-4b10-8b9a-374d8451721a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_eb66704b-9749-470f-94cd-89894e641115" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f6bc0fab-a1b5-4b10-8b9a-374d8451721a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_5327e06e-1f90-4ee5-90c5-ae28f98755d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f6bc0fab-a1b5-4b10-8b9a-374d8451721a" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_5327e06e-1f90-4ee5-90c5-ae28f98755d6" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails_1" xlink:type="simple" xlink:href="cna-20221231.xsd#NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails_1"/>

<link:definitionLink xlink:role="http://www.cna.com/role/NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails_1" xlink:type="extended" id="i7b851e88ec5b4d0b8b77bef36073be5d_NonInsuranceRevenuesfromContractswithCustomersPerformanceobligationDetails_1">

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_eb66704b-9749-470f-94cd-89894e641115" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_4af63bcd-b6ae-4418-a320-168c17b7466a" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofOperationsandComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofOperationsandComprehensiveIncomeLossDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofOperationsandComprehensiveIncomeLossDetails" xlink:type="extended" id="ib03b23c383f245adb5b2d6a559e943d1_ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofOperationsandComprehensiveIncomeLossDetails">

<link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_04530688-8c87-4ac7-b53a-7608c8e11b65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenuesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_RevenuesAbstract_04530688-8c87-4ac7-b53a-7608c8e11b65" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities_eee876c6-053e-41e3-81d4-9613d6be2621" xlink:href="cna-20221231.xsd#cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_04530688-8c87-4ac7-b53a-7608c8e11b65" xlink:to="loc_cna_NetInvestmentIncomeAndGainsLossesOnTradingSecurities_eee876c6-053e-41e3-81d4-9613d6be2621" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentsandDerivativesRealizedGainLoss_4feb36e7-653f-479e-843b-6a26157f1d9e" xlink:href="cna-20221231.xsd#cna_InvestmentsandDerivativesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_04530688-8c87-4ac7-b53a-7608c8e11b65" xlink:to="loc_cna_InvestmentsandDerivativesRealizedGainLoss_4feb36e7-653f-479e-843b-6a26157f1d9e" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_81c47b7c-e92d-4bf9-bb61-81959d281c47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Revenues"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_Revenues_81c47b7c-e92d-4bf9-bb61-81959d281c47" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_BenefitsLossesAndExpensesAbstract_13cb4ae7-7bd7-4a27-9c0c-4d9dcc855e3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BenefitsLossesAndExpensesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_BenefitsLossesAndExpensesAbstract_13cb4ae7-7bd7-4a27-9c0c-4d9dcc855e3a" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_023b6559-6f88-437d-aab7-94e4a3036c5d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_13cb4ae7-7bd7-4a27-9c0c-4d9dcc855e3a" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_023b6559-6f88-437d-aab7-94e4a3036c5d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_745e2047-30cb-476c-8872-dd6aa057edbf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_13cb4ae7-7bd7-4a27-9c0c-4d9dcc855e3a" xlink:to="loc_us-gaap_InterestExpense_745e2047-30cb-476c-8872-dd6aa057edbf" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_4d99523e-1ffe-47c3-b9bf-b9c72f8fa19c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpenses"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BenefitsLossesAndExpensesAbstract_13cb4ae7-7bd7-4a27-9c0c-4d9dcc855e3a" xlink:to="loc_us-gaap_OperatingExpenses_4d99523e-1ffe-47c3-b9bf-b9c72f8fa19c" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndIncomeLossFromSubsidiaries_0317810d-ef92-4ce4-a970-1149765a6e06" xlink:href="cna-20221231.xsd#cna_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndIncomeLossFromSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_cna_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAndIncomeLossFromSubsidiaries_0317810d-ef92-4ce4-a970-1149765a6e06" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_bd70ea48-6d49-464d-977a-2acb269e1abf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_bd70ea48-6d49-464d-977a-2acb269e1abf" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestments_ffa50408-c26a-42b3-aaee-2c3cdd3d7a92" xlink:href="cna-20221231.xsd#cna_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_cna_IncomeLossFromContinuingOperationsBeforeEquityMethodInvestments_ffa50408-c26a-42b3-aaee-2c3cdd3d7a92" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_EquityInNetIncomeLossOfSubsidiaries_ef913d94-9fa5-473a-abf7-f30207dee546" xlink:href="cna-20221231.xsd#cna_EquityInNetIncomeLossOfSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_cna_EquityInNetIncomeLossOfSubsidiaries_ef913d94-9fa5-473a-abf7-f30207dee546" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_fdc00f7f-8243-479a-8fac-4821986f7053" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_NetIncomeLoss_fdc00f7f-8243-479a-8fac-4821986f7053" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_EquityInOtherComprehensiveIncomeOfSubsidiaries_068c94a1-6691-4651-8e09-fc726dd3703f" xlink:href="cna-20221231.xsd#cna_EquityInOtherComprehensiveIncomeOfSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_cna_EquityInOtherComprehensiveIncomeOfSubsidiaries_068c94a1-6691-4651-8e09-fc726dd3703f" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_a5c6e627-ddb7-4a4a-b2fd-78b895a5f81f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_a5c6e627-ddb7-4a4a-b2fd-78b895a5f81f" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_3b3ae970-2f67-44eb-800b-fe8b88d4ed2b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_2323504d-90de-475d-bf3f-796530a9e542" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_3b3ae970-2f67-44eb-800b-fe8b88d4ed2b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_93ab96fe-b181-41c4-9f4f-7103239b9d3f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_3b3ae970-2f67-44eb-800b-fe8b88d4ed2b" xlink:to="loc_srt_ConsolidatedEntitiesAxis_93ab96fe-b181-41c4-9f4f-7103239b9d3f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_93ab96fe-b181-41c4-9f4f-7103239b9d3f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_93ab96fe-b181-41c4-9f4f-7103239b9d3f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_93ab96fe-b181-41c4-9f4f-7103239b9d3f_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_7ddb9b73-5dd7-4680-b6db-6dc94c5415d5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_93ab96fe-b181-41c4-9f4f-7103239b9d3f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_7ddb9b73-5dd7-4680-b6db-6dc94c5415d5" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_32c70051-30e5-40b3-b7de-e766982e91fa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ParentCompanyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_7ddb9b73-5dd7-4680-b6db-6dc94c5415d5" xlink:to="loc_srt_ParentCompanyMember_32c70051-30e5-40b3-b7de-e766982e91fa" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantBalanceSheetsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantBalanceSheetsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantBalanceSheetsDetails" xlink:type="extended" id="ib0fd1686abae43c9b15b619c1c73eb99_ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantBalanceSheetsDetails">

<link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentInSubsidiaries_89df83ee-523d-42ff-b49e-3a209556227f" xlink:href="cna-20221231.xsd#cna_InvestmentInSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:to="loc_cna_InvestmentInSubsidiaries_89df83ee-523d-42ff-b49e-3a209556227f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Cash_c1a66593-da62-4ccb-8791-e4d85f4371c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Cash"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:to="loc_us-gaap_Cash_c1a66593-da62-4ccb-8791-e4d85f4371c2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_34c918d2-4028-476f-8203-6af84c462a5f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:to="loc_us-gaap_ShortTermInvestments_34c918d2-4028-476f-8203-6af84c462a5f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueFromAffiliates_923afe4c-24e0-4bae-b47c-e8ca1753e644" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DueFromAffiliates"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:to="loc_us-gaap_DueFromAffiliates_923afe4c-24e0-4bae-b47c-e8ca1753e644" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_a78475fb-d1bf-4de2-a9b9-eacb10b1f6a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_1d584722-3035-4380-8b53-bfe1e7b80d0f" xlink:to="loc_us-gaap_Assets_a78475fb-d1bf-4de2-a9b9-eacb10b1f6a6" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermBorrowings_5deedfa6-bbd1-4382-a415-b5faa6f49d85" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermBorrowings"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:to="loc_us-gaap_ShortTermBorrowings_5deedfa6-bbd1-4382-a415-b5faa6f49d85" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_3334eabe-280d-47ce-b39f-0a6108536eba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtNoncurrent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_3334eabe-280d-47ce-b39f-0a6108536eba" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_bfce7713-1d42-4be4-b589-3e2ec22d49d8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:to="loc_us-gaap_OtherLiabilities_bfce7713-1d42-4be4-b589-3e2ec22d49d8" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_5d0cf7b9-2798-49e3-8bac-d4307e5fd852" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_742560ec-4737-41b0-bf2e-134a1996f984" xlink:to="loc_us-gaap_Liabilities_5d0cf7b9-2798-49e3-8bac-d4307e5fd852" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_07815e87-6053-4a20-9450-6a6b1aeb9266" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_CommonStockValue_07815e87-6053-4a20-9450-6a6b1aeb9266" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_ad8a4eb7-f164-4e42-9175-646b56a0c4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_ad8a4eb7-f164-4e42-9175-646b56a0c4b5" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_fb2d16b2-d0b1-4d32-9f63-b43cafb0fbac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_fb2d16b2-d0b1-4d32-9f63-b43cafb0fbac" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_57c45693-6461-4f5c-9923-73836477e43b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_57c45693-6461-4f5c-9923-73836477e43b" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValue_31e18158-a06f-477e-8734-a727b56f2b03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockValue"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_TreasuryStockValue_31e18158-a06f-477e-8734-a727b56f2b03" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c0da0bdb-4869-48bd-86ae-dded5d47928d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_a8bf4a74-34d4-4daf-acbb-dbade87afe30" xlink:to="loc_us-gaap_StockholdersEquity_c0da0bdb-4869-48bd-86ae-dded5d47928d" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_c62ebf46-0c96-4667-acbd-966a5c73a612" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_c62ebf46-0c96-4667-acbd-966a5c73a612" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:href="cna-20221231.xsd#cna_ScheduleIiBalanceSheetParentheticalAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_43d81477-fcc6-4bb5-8afe-677bfdd6a96d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_43d81477-fcc6-4bb5-8afe-677bfdd6a96d" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_d54ec3b8-a532-4042-9b82-1d1fc9c71f83" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesAuthorized"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_d54ec3b8-a532-4042-9b82-1d1fc9c71f83" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_b678181a-6e85-4358-ad5f-267f6e498c13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesIssued"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:to="loc_us-gaap_CommonStockSharesIssued_b678181a-6e85-4358-ad5f-267f6e498c13" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_d37b0c6a-72c8-48be-8183-9e9e6b1e6cf2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_d37b0c6a-72c8-48be-8183-9e9e6b1e6cf2" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockShares_a1c5aee0-fe83-4653-8c67-464b82e9fd28" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TreasuryStockShares"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleIiBalanceSheetParentheticalAbstract_750ab047-a86c-44c5-a59f-154a1b8e6b7e" xlink:to="loc_us-gaap_TreasuryStockShares_a1c5aee0-fe83-4653-8c67-464b82e9fd28" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_51deb1ad-9c85-458b-8f3f-2eb536768f4e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_ec6acb1e-3320-4c9b-9e39-21013db2757e" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_51deb1ad-9c85-458b-8f3f-2eb536768f4e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_07098e36-9e07-42ab-9b09-cc92382d25c4" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_51deb1ad-9c85-458b-8f3f-2eb536768f4e" xlink:to="loc_srt_ConsolidatedEntitiesAxis_07098e36-9e07-42ab-9b09-cc92382d25c4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_07098e36-9e07-42ab-9b09-cc92382d25c4_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_07098e36-9e07-42ab-9b09-cc92382d25c4" xlink:to="loc_srt_ConsolidatedEntitiesDomain_07098e36-9e07-42ab-9b09-cc92382d25c4_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_bdc07c88-7cdf-4c78-9ee8-d363e319be8e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_07098e36-9e07-42ab-9b09-cc92382d25c4" xlink:to="loc_srt_ConsolidatedEntitiesDomain_bdc07c88-7cdf-4c78-9ee8-d363e319be8e" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_148e392a-1a43-49bb-a659-a681ecba2abe" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ParentCompanyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_bdc07c88-7cdf-4c78-9ee8-d363e319be8e" xlink:to="loc_srt_ParentCompanyMember_148e392a-1a43-49bb-a659-a681ecba2abe" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofCashFlowsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofCashFlowsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofCashFlowsDetails" xlink:type="extended" id="i702e7aa73dff479f86ba1b510d2d0eb2_ScheduleIICondensedFinancialInformationofRegistrantParentCompanyScheduleofCondensedFinancialInformationofRegistrantStatementsofCashFlowsDetails">

<link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_d52c569b-beb4-4b73-b423-5aad09476291" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_d52c569b-beb4-4b73-b423-5aad09476291" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_24006659-dd7e-4bf0-90f7-69858aff66ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_d52c569b-beb4-4b73-b423-5aad09476291" xlink:to="loc_us-gaap_NetIncomeLoss_24006659-dd7e-4bf0-90f7-69858aff66ec" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_d52c569b-beb4-4b73-b423-5aad09476291" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromSubsidiariesNetOfTax_2d5e2382-46ec-42a6-995b-bc46efab1df4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromSubsidiariesNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:to="loc_us-gaap_IncomeLossFromSubsidiariesNetOfTax_2d5e2382-46ec-42a6-995b-bc46efab1df4" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries_54f5c527-ccd1-45c8-80f8-cb22baee830d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:to="loc_us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries_54f5c527-ccd1-45c8-80f8-cb22baee830d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentsandDerivativesRealizedGainLoss_4a3c8cf9-b58e-415c-9526-0b1a21ac6676" xlink:href="cna-20221231.xsd#cna_InvestmentsandDerivativesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:to="loc_cna_InvestmentsandDerivativesRealizedGainLoss_4a3c8cf9-b58e-415c-9526-0b1a21ac6676" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_00bb1b8f-abce-478d-a4d2-c9707dd4b7bc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:to="loc_us-gaap_OtherOperatingActivitiesCashFlowStatement_00bb1b8f-abce-478d-a4d2-c9707dd4b7bc" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_feac3af2-742c-4073-80b9-2285fb1e9321" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_ea54bd41-de17-49b4-bc79-84528bcd34c2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_feac3af2-742c-4073-80b9-2285fb1e9321" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ChangeInShortTermInvestments_7f6c5048-47fa-4a79-8b89-422d993abd03" xlink:href="cna-20221231.xsd#cna_ChangeInShortTermInvestments"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:to="loc_cna_ChangeInShortTermInvestments_7f6c5048-47fa-4a79-8b89-422d993abd03" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CapitalContributionstoSubsidiaries_23431fae-7d2a-4dad-84df-b694555a75aa" xlink:href="cna-20221231.xsd#cna_CapitalContributionstoSubsidiaries"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:to="loc_cna_CapitalContributionstoSubsidiaries_23431fae-7d2a-4dad-84df-b694555a75aa" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_cfd9ee93-b56f-4857-a691-ecbf5236f191" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:to="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_cfd9ee93-b56f-4857-a691-ecbf5236f191" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_36ea4840-3fa3-4086-948e-fcb3a1159edd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_afef9f91-d0ef-46cf-a82e-f4502d45a70a" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_36ea4840-3fa3-4086-948e-fcb3a1159edd" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_2d442ef0-e7d8-4468-8b06-e306c59c9918" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_2d442ef0-e7d8-4468-8b06-e306c59c9918" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_62c065ad-72d2-4c13-9bd2-480e30da4eab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_62c065ad-72d2-4c13-9bd2-480e30da4eab" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_c5df9d3b-e1d5-4558-9c1a-a12e5156af6f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RepaymentsOfLongTermDebt"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_c5df9d3b-e1d5-4558-9c1a-a12e5156af6f" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_78a5860d-c777-4708-bfb3-4b7fab24dd40" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_78a5860d-c777-4708-bfb3-4b7fab24dd40" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_8207edeb-84c1-4271-8624-34b01af4c583" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities_8207edeb-84c1-4271-8624-34b01af4c583" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_14c607df-238b-46e1-bf80-74a98ad75f58" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_7e9e81a6-3bde-4404-9b11-568a388e758c" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_14c607df-238b-46e1-bf80-74a98ad75f58" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_cecc9690-e579-4647-ada9-03e7638abcaf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_cecc9690-e579-4647-ada9-03e7638abcaf" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_a9e529a6-f09f-4fe6-9b5d-3027287b31ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_a9e529a6-f09f-4fe6-9b5d-3027287b31ea" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_afc0673d-ce13-4c6f-b86b-faa9a0eb079e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_32852eff-437e-4d51-aa99-496b7e60d8ed" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9b4a2916-4313-49d6-a371-79869d2ec7f2" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_32852eff-437e-4d51-aa99-496b7e60d8ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_65552845-6085-4af6-8a35-8bde7dd9716a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_32852eff-437e-4d51-aa99-496b7e60d8ed" xlink:to="loc_srt_ConsolidatedEntitiesAxis_65552845-6085-4af6-8a35-8bde7dd9716a" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_65552845-6085-4af6-8a35-8bde7dd9716a_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_65552845-6085-4af6-8a35-8bde7dd9716a" xlink:to="loc_srt_ConsolidatedEntitiesDomain_65552845-6085-4af6-8a35-8bde7dd9716a_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_9fd9fb20-94fc-437c-abe2-c8ddb774adc2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_65552845-6085-4af6-8a35-8bde7dd9716a" xlink:to="loc_srt_ConsolidatedEntitiesDomain_9fd9fb20-94fc-437c-abe2-c8ddb774adc2" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_a0f6b918-8df5-400d-a386-f6a044d1d94b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ParentCompanyMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_9fd9fb20-94fc-437c-abe2-c8ddb774adc2" xlink:to="loc_srt_ParentCompanyMember_a0f6b918-8df5-400d-a386-f6a044d1d94b" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyNarrativeDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleIICondensedFinancialInformationofRegistrantParentCompanyNarrativeDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleIICondensedFinancialInformationofRegistrantParentCompanyNarrativeDetails" xlink:type="extended" id="if91aafaa9c9442a9b4792ab9f1c12a16_ScheduleIICondensedFinancialInformationofRegistrantParentCompanyNarrativeDetails">

<link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_8bba7cb2-bfff-4e29-80d0-f2f8177b5ece" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_428cf16d-69e1-4bd7-bccb-982de1c1391c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_8bba7cb2-bfff-4e29-80d0-f2f8177b5ece" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_428cf16d-69e1-4bd7-bccb-982de1c1391c" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_20699690-e6dc-45d6-9338-0549a030ed99" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_8bba7cb2-bfff-4e29-80d0-f2f8177b5ece" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_20699690-e6dc-45d6-9338-0549a030ed99" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_54d0e07b-e938-48cd-92ca-059c224e5f81" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_20699690-e6dc-45d6-9338-0549a030ed99" xlink:to="loc_srt_OwnershipAxis_54d0e07b-e938-48cd-92ca-059c224e5f81" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_54d0e07b-e938-48cd-92ca-059c224e5f81_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_54d0e07b-e938-48cd-92ca-059c224e5f81" xlink:to="loc_srt_OwnershipDomain_54d0e07b-e938-48cd-92ca-059c224e5f81_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_3aa7a04d-3021-42a4-8e3d-55bd2ef19d49" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_54d0e07b-e938-48cd-92ca-059c224e5f81" xlink:to="loc_srt_OwnershipDomain_3aa7a04d-3021-42a4-8e3d-55bd2ef19d49" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_CNAFConsolidatedMember_31596c95-4de5-484f-b4f8-1b8f85374875" xlink:href="cna-20221231.xsd#cna_CNAFConsolidatedMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_3aa7a04d-3021-42a4-8e3d-55bd2ef19d49" xlink:to="loc_cna_CNAFConsolidatedMember_31596c95-4de5-484f-b4f8-1b8f85374875" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_397cce37-f5e9-4cce-b13d-9a41b503850c" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_LegalEntityAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_20699690-e6dc-45d6-9338-0549a030ed99" xlink:to="loc_dei_LegalEntityAxis_397cce37-f5e9-4cce-b13d-9a41b503850c" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_397cce37-f5e9-4cce-b13d-9a41b503850c_default" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_397cce37-f5e9-4cce-b13d-9a41b503850c" xlink:to="loc_dei_EntityDomain_397cce37-f5e9-4cce-b13d-9a41b503850c_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_ee53fcfe-0b91-4592-bddc-2d3f2d628eba" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_397cce37-f5e9-4cce-b13d-9a41b503850c" xlink:to="loc_dei_EntityDomain_ee53fcfe-0b91-4592-bddc-2d3f2d628eba" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_LoewsMember_406caaf2-1174-40c0-9c39-b4a27cf2ce71" xlink:href="cna-20221231.xsd#cna_LoewsMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_ee53fcfe-0b91-4592-bddc-2d3f2d628eba" xlink:to="loc_cna_LoewsMember_406caaf2-1174-40c0-9c39-b4a27cf2ce71" xlink:type="arc" order="0"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleVValuationandQualifyingAccountsScheduleofvaluationandqualifyingaccountsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleVValuationandQualifyingAccountsScheduleofvaluationandqualifyingaccountsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleVValuationandQualifyingAccountsScheduleofvaluationandqualifyingaccountsDetails" xlink:type="extended" id="idcc4de83e72b44f78a96a0f6c5646d2d_ScheduleVValuationandQualifyingAccountsScheduleofvaluationandqualifyingaccountsDetails">

<link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_46312c1f-fb14-456c-9916-eb908dac0c31" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_46312c1f-fb14-456c-9916-eb908dac0c31" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_8c21f915-1027-49f3-94a0-74db1c0936ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_8c21f915-1027-49f3-94a0-74db1c0936ba" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_a3a34d96-1ef2-414b-ae82-a351b3a7afbd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_a3a34d96-1ef2-414b-ae82-a351b3a7afbd" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_5dc0ee5c-b4a6-43f1-9e87-3a17143bd8b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_5dc0ee5c-b4a6-43f1-9e87-3a17143bd8b1" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_9277cf7e-46ff-4411-bf2c-69e3b6974724" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesDeductions"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_c097afbd-a1bc-4d49-88ec-5d846d67628e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_9277cf7e-46ff-4411-bf2c-69e3b6974724" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_91718ddc-6a69-441a-950a-2682aea0fc03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c0d6b6f8-7b15-48ab-ae59-282e138384ed" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_46312c1f-fb14-456c-9916-eb908dac0c31" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c0d6b6f8-7b15-48ab-ae59-282e138384ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1b78a30d-82c8-459e-abb6-5001ea725eef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_c0d6b6f8-7b15-48ab-ae59-282e138384ed" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1b78a30d-82c8-459e-abb6-5001ea725eef" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_1b78a30d-82c8-459e-abb6-5001ea725eef_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1b78a30d-82c8-459e-abb6-5001ea725eef" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_1b78a30d-82c8-459e-abb6-5001ea725eef_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_d45eeb6b-b997-469c-a313-242e80240e67" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_1b78a30d-82c8-459e-abb6-5001ea725eef" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_d45eeb6b-b997-469c-a313-242e80240e67" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesRealEstateMember_1f1acb1d-61f3-47e9-a8ea-fd86b27e0a19" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllowanceForLoanAndLeaseLossesRealEstateMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_d45eeb6b-b997-469c-a313-242e80240e67" xlink:to="loc_us-gaap_AllowanceForLoanAndLeaseLossesRealEstateMember_1f1acb1d-61f3-47e9-a8ea-fd86b27e0a19" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForReceivableFromInsuranceProviderMember_da0d80b0-2715-4a0a-85b7-9fb896f7233f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllowanceForReceivableFromInsuranceProviderMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_d45eeb6b-b997-469c-a313-242e80240e67" xlink:to="loc_us-gaap_AllowanceForReceivableFromInsuranceProviderMember_da0d80b0-2715-4a0a-85b7-9fb896f7233f" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_28b30f24-550b-43ff-aa23-057ff97310d7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllowanceForCreditLossMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_d45eeb6b-b997-469c-a313-242e80240e67" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_28b30f24-550b-43ff-aa23-057ff97310d7" xlink:type="arc" order="2"/>

</link:definitionLink>

<link:roleRef roleURI="http://www.cna.com/role/ScheduleVISupplementalInformationConcerningPropertyandCasualtyInsuranceOperationsDetails" xlink:type="simple" xlink:href="cna-20221231.xsd#ScheduleVISupplementalInformationConcerningPropertyandCasualtyInsuranceOperationsDetails"/>

<link:definitionLink xlink:role="http://www.cna.com/role/ScheduleVISupplementalInformationConcerningPropertyandCasualtyInsuranceOperationsDetails" xlink:type="extended" id="id22b1ebbc3c746e1803807868a42e3cf_ScheduleVISupplementalInformationConcerningPropertyandCasualtyInsuranceOperationsDetails">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts_248a7296-2040-4a7c-a132-a6804d9bc0ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDeferredPolicyAcquisitionCosts_248a7296-2040-4a7c-a132-a6804d9bc0ee" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense_16d9d843-d09d-49bc-96e2-1433552f586c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersReservesForUnpaidClaimsAndClaimsAdjustmentExpense_16d9d843-d09d-49bc-96e2-1433552f586c" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDiscountDeductedFromReserves_c8e67c56-485a-4c40-b6b0-c38a56427181" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDiscountDeductedFromReserves"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersDiscountDeductedFromReserves_c8e67c56-485a-4c40-b6b0-c38a56427181" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums_a0571323-5818-4ec6-b82b-6af2b33a6bf3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersUnearnedPremiums_a0571323-5818-4ec6-b82b-6af2b33a6bf3" xlink:type="arc" order="3"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten_ad8d31b6-453c-4d3e-8c95-11b5fe8b5a54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPremiumsWritten_ad8d31b6-453c-4d3e-8c95-11b5fe8b5a54" xlink:type="arc" order="4"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums_fbe8dfdf-2ce1-4a5b-963e-9d00760e3395" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersEarnedPremiums_fbe8dfdf-2ce1-4a5b-963e-9d00760e3395" xlink:type="arc" order="5"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome_5b661b82-36ea-423e-b58b-25b8888d549e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersNetInvestmentIncome_5b661b82-36ea-423e-b58b-25b8888d549e" xlink:type="arc" order="6"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense_d36ce493-337a-4aa4-9f13-0cc6802dfa21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense_d36ce493-337a-4aa4-9f13-0cc6802dfa21" xlink:type="arc" order="7"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_a55e2e0c-d512-47d2-97f1-b49694edac8b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense_a55e2e0c-d512-47d2-97f1-b49694edac8b" xlink:type="arc" order="8"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts_067593cc-db66-4b0e-830a-fd7d32f82841" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAmortizationOfDeferredPolicyAcquisitionCosts_067593cc-db66-4b0e-830a-fd7d32f82841" xlink:type="arc" order="9"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense_67db7a80-dc4c-4baa-848e-6263157a9ebf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPaidClaimsAndClaimsAdjustmentExpense_67db7a80-dc4c-4baa-848e-6263157a9ebf" xlink:type="arc" order="10"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_ScheduleViSupplementalInformationParentheticalAbstract_820c1104-719a-41ae-b487-f4ec5f02f174" xlink:href="cna-20221231.xsd#cna_ScheduleViSupplementalInformationParentheticalAbstract"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_cna_ScheduleViSupplementalInformationParentheticalAbstract_820c1104-719a-41ae-b487-f4ec5f02f174" xlink:type="arc" order="11"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersInterestRateAtWhichDiscountComputed_60217c40-9d51-4966-8906-cbdd2993e3f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersInterestRateAtWhichDiscountComputed"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cna_ScheduleViSupplementalInformationParentheticalAbstract_820c1104-719a-41ae-b487-f4ec5f02f174" xlink:to="loc_us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersInterestRateAtWhichDiscountComputed_60217c40-9d51-4966-8906-cbdd2993e3f6" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersTable_efeae21c-57da-4a1a-a3a3-46c52ceb7c10" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersTable"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_7f7a4615-040e-46e6-9386-c0e362d962e2" xlink:to="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersTable_efeae21c-57da-4a1a-a3a3-46c52ceb7c10" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrantAxis_5bf4cefd-b2ba-4171-a4e6-32e450d3d970" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrantAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersTable_efeae21c-57da-4a1a-a3a3-46c52ceb7c10" xlink:to="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrantAxis_5bf4cefd-b2ba-4171-a4e6-32e450d3d970" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain_5bf4cefd-b2ba-4171-a4e6-32e450d3d970_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrantAxis_5bf4cefd-b2ba-4171-a4e6-32e450d3d970" xlink:to="loc_srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain_5bf4cefd-b2ba-4171-a4e6-32e450d3d970_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain_79a304ae-37b7-4a7b-a13e-1b3157047819" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersByAffiliationWithRegistrantAxis_5bf4cefd-b2ba-4171-a4e6-32e450d3d970" xlink:to="loc_srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain_79a304ae-37b7-4a7b-a13e-1b3157047819" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedPropertyAndCasualtyInsuranceEntityMember_e472be48-f619-4d24-bf60-da0e0c08e313" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedPropertyAndCasualtyInsuranceEntityMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_PropertyCasualtyInsuranceUnderwritersAffiliationWithRegistrantDomain_79a304ae-37b7-4a7b-a13e-1b3157047819" xlink:to="loc_srt_ConsolidatedPropertyAndCasualtyInsuranceEntityMember_e472be48-f619-4d24-bf60-da0e0c08e313" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bee16bac-4538-40bf-a2c0-a363d926840d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersTable_efeae21c-57da-4a1a-a3a3-46c52ceb7c10" xlink:to="loc_srt_RangeAxis_bee16bac-4538-40bf-a2c0-a363d926840d" xlink:type="arc" order="2"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bee16bac-4538-40bf-a2c0-a363d926840d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bee16bac-4538-40bf-a2c0-a363d926840d" xlink:to="loc_srt_RangeMember_bee16bac-4538-40bf-a2c0-a363d926840d_default" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e5babb89-eb3c-49fc-a65d-a9e0fae979fa" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bee16bac-4538-40bf-a2c0-a363d926840d" xlink:to="loc_srt_RangeMember_e5babb89-eb3c-49fc-a65d-a9e0fae979fa" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_2262331e-9ff6-4767-bbfa-cce6f1923262" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e5babb89-eb3c-49fc-a65d-a9e0fae979fa" xlink:to="loc_srt_MinimumMember_2262331e-9ff6-4767-bbfa-cce6f1923262" xlink:type="arc" order="0"/>

<link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_79d46833-1424-4157-a4dd-c84dbe3aa27a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e5babb89-eb3c-49fc-a65d-a9e0fae979fa" xlink:to="loc_srt_MaximumMember_79d46833-1424-4157-a4dd-c84dbe3aa27a" xlink:type="arc" order="1"/>

</link:definitionLink>

<link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-roles-2022.xsd#eedm"/>

<link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementAbstract"/>

<link:loc xlink:type="locator" xlink:label="loc_cna_InvestmentsandDerivativesRealizedGainLoss_53f1a317-02a9-42c3-9da0-d0c5351d9086" xlink:href="cna-20221231.xsd#cna_InvestmentsandDerivativesRealizedGainLoss"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="loc_cna_InvestmentsandDerivativesRealizedGainLoss_53f1a317-02a9-42c3-9da0-d0c5351d9086" xlink:type="arc" order="1"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfOtherComprehensiveIncomeAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfOtherComprehensiveIncomeAbstract"/>

<link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>

<link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementOfOtherComprehensiveIncomeAbstract" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" order="1"/>

</link:definitionLink>

</link:linkbase>

4 Subsequent Filings that Reference this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 8/04/23  CNA Financial Corp.               424B2                  2:614K                                   Toppan Merrill/FA
 8/02/23  CNA Financial Corp.               424B3                  1:599K                                   Toppan Merrill/FA
 5/19/23  CNA Financial Corp.               424B5                  2:627K                                   Toppan Merrill/FA
 5/17/23  CNA Financial Corp.               424B3                  1:608K                                   Toppan Merrill/FA

15 Previous Filings that this Filing References

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/08/22  CNA Financial Corp.               10-K       12/31/21  163:34M
12/31/20  CNA Financial Corp.               8-K:1,7,9  12/30/20   14:1.2M
 8/10/20  CNA Financial Corp.               8-K:5,9     8/10/20   14:382K
 3/20/20  CNA Financial Corp.               DEF 14A     4/29/20    1:1.5M                                   Toppan Merrill-FA
 2/11/20  CNA Financial Corp.               10-K       12/31/19  169:42M
12/19/19  CNA Financial Corp.               8-K:1,9    12/19/19   13:1M
10/25/17  CNA Financial Corp.               8-K:5      10/25/17    2:111K
 5/01/17  CNA Financial Corp.               10-Q        3/31/17   67:11M
 8/04/15  CNA Financial Corp.               10-Q        6/30/15   73:16M
 9/01/10  Cna Financial Corp.               8-K:1,7,9   8/31/10    7:867K                                   Donnelley … Solutions/FA
 7/16/10  Cna Financial Corp.               8-K:1,7,9   7/14/10    3:1.2M                                   Donnelley … Solutions/FA
 2/26/08  Cna Financial Corp.               10-K       12/31/07   20:2.1M                                   Bowne Boc/FA
 2/23/07  Cna Financial Corp.               10-K       12/31/06    9:1.9M                                   Bowne Boc/FA
 8/08/06  Cna Financial Corp.               8-K:1,7,9   8/08/06    3:99K                                    Donnelley … Solutions/FA
10/09/98  Cna Financial Corp.               S-8        10/09/98    7:102K

↑Top

Filing Submission 0000021175-23-000006 – Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)

CNA Financial Corp. – ‘10-K’ for 12/31/22 – ‘EX-101.DEF’

On: Tuesday, 2/7/23, at 4:39pm ET · For: 12/31/22 · Accession #: 21175-23-6 · File #: 1-05823

Annual Report — Form 10-KFiling Table of Contents

‘EX-101.DEF’ — XBRL Definitions — cna-20221231_def

This Exhibit is an XBRL XML File.

4 Subsequent Filings that Reference this Filing

15 Previous Filings that this Filing References

Annual Report — Form 10-K

Filing Table of Contents