A third party in a guaranty contract is primarily liable to the creditor for the debtor's debt.

Third Party

A third party is an entity that is neither the principal nor the counterparty in a transaction, agreement, or legal case but may have an interest or be indirectly involved.

Guaranty Contract

A legal agreement wherein a guarantor agrees to fulfill the obligations of a debtor to a lender, should the debtor fail to do so.

Creditor

An entity (person or institution) that lends money or extends credit to another entity, with the expectation of being repaid in the future.