verifier vs verify

verifier is a noun but verify is not a noun.

Word	Noun	Adjective	Verb	Adverb
verifier	Yes	No	No	No
verify	No	No	Yes	No

verifier (noun)	verify (noun)
someone who vouches for another or for the correctness of a statement

verifier (verb)	verify (verb)
	confirm the truth of
	to declare or affirm solemnly and formally as true
	attach or append a legal verification to (a pleading or petition)
	check or regulate (a scientific experiment) by conducting a parallel experiment or comparing with another standard