attestant
(noun)
noun
1. (law) a person who attests to the genuineness of a document or signature by adding their own signature
Similar word(s): attestor, witness
Definition categories: person, signatory, signer
2. someone who affirms or vouches for the correctness or truth or genuineness of something
Similar word(s): attester
Definition categories: person, informant, witness, witnesser