A second party that co-signs on your loan to ensure a lender that if you are not making the promised payments they will be responsible for the scheduled payments.
An additional person who signs a loan document and takes equal responsibility for the debt. A borrower may want to use a co-signer if their credit or financial situation is not good enough to qualify for a loan on their own. A co-signer is legally responsible for the loan and the shared account will appear on their credit report. Having a co-signer is only helpful if the co-signer's credit or financial standing is better than the primary lender.
Individual (or entity) who signs a legal document on an equal basis with the other signer(s). On a promissory note, the co-signer is jointly liable with the other signers for repayment of the full debt.