Surety

[Sarah]

One who is bound with and for another who is primarily liable,and who is called the principal; one who engages to answer foranother's appearance in court, or for his payment of a debt, or forperformance of some act; a bondsman; a bail.He that is surety for a stranger shall smart for it. Prov. xi. 15.

[Gregory]

A person who takes responsibility for anothers performance of an undertaking, for example their appearing in court or paying a debt.