Co-sign and Testify

Co-sign verb - Sign jointly.

Testify and co-sign are semantically related. in pledge topic. In some cases you can use "Testify" instead a verb phrase "Co-sign", when it comes to topics like give assurance.

Testify verb - To make a solemn declaration under oath for the purpose of establishing a fact.

Co-sign and testify are semantically related. Sometimes you can replace phrase "Co-sign" with "Testify", this terms are similar.