informant vs attestant

informant and attestant both are nouns.

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

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

informant: 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 informant include attester, deponent, deposer, testifier.

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