Definition

1. Verb:
   • To sign a document jointly with another person, thereby assuming shared legal responsibility for the obligations in that document. This most commonly refers to endorsing another person's signature on a loan or lease agreement to guarantee its repayment or fulfillment.
   • To formally endorse or support something, such as an idea or statement, by adding one's signature or public approval alongside another's.

Usage

The verb co-sign is used when a person with stronger credit or financial standing agrees to be equally responsible for a debt or contract if the primary borrower or signer fails to meet their obligations. It is a formal, legal action.

Examples

• Financial/Contractual Context:

  • The bank required a parent to co-sign the student loan application.
  • Because of my limited credit history, my sister had to co-sign the apartment lease with me.
  • They co-signed the mortgage, making them both liable for the payments.

• Endorsement Context:

  • Five leading scientists co-signed the open letter warning about climate change.
  • The celebrity co-signed the statement released by the charity.

Advanced Usage

• "to co-sign for someone": This phrasal construction specifies the person being assisted.
  • I can't get a car loan unless you agree to co-sign for me.
• The act of providing this guarantee is called "co-signing" (gerund/noun).
  • Her co-signing on the loan helped me get approved.

Variants and Related Words

• Co-signer (noun): The person who provides the signature and assumes the joint responsibility.
  • If the borrower defaults, the co-signer is legally responsible for the debt.
• Co-signatory (noun): A more formal term for a person or party that signs a document jointly with others.
  • All co-signatories to the treaty must ratify it.

Synonyms

• Endorse: To sign one's name on the back of (a check) or to declare one's public approval or support.
• Guarantee: To provide a formal promise or assurance, often accepting financial liability.
• Underwrite: To sign and accept liability, or to pledge to buy all unsold shares (in finance).

Related Phrasal Verbs / Constructions

• Co-sign on (something): To be a co-signer for a specific agreement.
  • He asked me to co-sign on the business loan.

Important Notes

Being a co-signer is a significant legal and financial commitment. A co-signer's credit is impacted by the loan, and they are fully liable if the primary borrower fails to pay. It is not merely a character reference.

Verb

1. sign and endorse (another person's signature), as for a loan
2. sign jointly
   • Husband and wife co-signed the lease