"To repay the bond" means to pay back the money borrowed by an entity (such as a government or company) from individuals or investors who purchased the bond. Full definition
Lastly, since bonds are debt, you can lose money if the bond issuer has financial struggles and is unable to repay bond investors. (fool.com)
For bonds, a catastrophic event is called a default, where the bond issuer either can't make the regular interest payments or fails to repay the bond value altogether. (mindfullyinvesting.com)
Though as CreditSights» Simon Adamson noted, the firm will do everything it can to repay these bonds so it can issue them again in the future. (businessinsider.com)