Final answer:
Entities that pay on a debt they did not originally contract for are known as guarantors or sureties, who pledge to meet the debt obligations if the primary debtor defaults.
Step-by-step explanation:
Entities that make payment on an obligation or debt but are not parties of the contract that created the debt are called guarantors or sureties. These terms refer to those who have agreed to be responsible for the debt if the primary debtor fails to pay. A guarantor often backs the debtor by pledging to pay the debt or perform an obligation if the debtor defaults. A surety is similar but often involves a formal assumption of liability and may be secured with the surety's assets or a pledge.
A debtor is the party who has the primary responsibility for paying back the debt. Contrarily, a creditor is the entity that has provided the loan or credit to the debtor. And a cosigner is another person or firm who legally pledges to repay some or all of the money on a loan if the original borrower does not, similar to a guarantor.