Guaranty

As a verb, to agree to be responsible for the payment of another's debt or the performance of another's duty, liability, or obligation if that person does not perform as he or she is legally obligated to do; to assume the responsibility of a guarantor; to warrant.

As a noun, an undertaking or promise that is collateral to the primary or principal obligation and that binds the guarantor to performance in the event of nonperformance by the principal obligor.

A guaranty is a contract that some particular thing shall be done exactly as it is agreed to be done, whether it is to be done by one person or another, and whether there be a prior or principal contractor or not.

A sample guaranty