witnesser vs attestant

witnesser and attestant both are nouns.

Word	Noun	Adjective	Verb	Adverb
witnesser	Yes	No	No	No
attestant	Yes	No	No	No

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

witnesser: someone who sees an event and reports what happened
attestant: someone who affirms or vouches for the correctness or truth or genuineness of something

Other hyponyms of witnesser include attester, deponent, deposer, testifier.

witnesser (noun)	attestant (noun)
someone who sees an event and reports what happened	(law) a person who attests to the genuineness of a document or signature by adding their own signature
	someone who affirms or vouches for the correctness or truth or genuineness of something