attestor vs signatory

attestor and signatory both are nouns.

Word	Noun	Adjective	Verb	Adverb
attestor	Yes	No	No	No
signatory	Yes	No	No	No

As nouns, signatory is a hypernym of attestor; that is, signatory is a word with a broader meaning than attestor:

attestor: (law) a person who attests to the genuineness of a document or signature by adding their own signature
signatory: someone who signs and is bound by a document

Other hypernyms of attestor include signer.

attestor (noun)	signatory (noun)
(law) a person who attests to the genuineness of a document or signature by adding their own signature	someone who signs and is bound by a document