An unauthorized signature may bind a principal who allowed the signature to be made through his own negligence.

Unauthorized Signature

An unauthorized signature is a signature made without the express permission of the person whose name is signed, often considered fraudulent or voidable.

Negligence

A legal concept where an individual fails to exercise a reasonable level of care, resulting in harm or damage to another person.

Principal

In law, a principal can refer to a party who grants authority to an agent to act in their stead; in finance, it can refer to the original amount of money invested or loaned, before any interest.