To write (something) with one's own hand
To make (a check, etc.) payable to another person by thus signing one's name and specifying the payee
To engage by written contract; sign on
To authorize (someone) to receive or access electronic texts or services, especially over the Internet.
Find another word for undersign. In this page you can discover 8 synonyms, antonyms, idiomatic expressions, and related words for undersign, like: autograph, endorse, inscribe, sign, subscribe, put one's John Hancock on, set one's hand to and law.