signatory vs witness

signatory and witness both are nouns.

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

As nouns, witness is a hyponym of signatory; that is, witness is a word with a more specific, narrower meaning than signatory:

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

Other hyponyms of signatory include cosignatory, cosigner, cosigner, abhorrer, endorser, indorser, attestant, attestator, attestor.

signatory (noun)	witness (noun)
someone who signs and is bound by a document	testimony by word or deed to your religious faith
	someone who sees an event and reports what happened
	a close observer; someone who looks at something (such as an exhibition of some kind)
	(law) a person who attests to the genuineness of a document or signature by adding their own signature
	(law) a person who testifies under oath in a court of law

signatory (verb)	witness (verb)
	be a witness to
	perceive or be contemporaneous with