Another person who signs his or her name on a loan, debt or other agreement of obligation (including lease) where the person agrees to act as a guarantor in the event the primary debtor does not pay. A cosigner is responsible for the entire amount of the loan or debt. Cosigners are commonly used for lease and credit card agreements when the primary party has poor credit.
COSIGNER
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.