verifier vs voucher

verifier and voucher both are nouns.

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

As nouns, verifier and voucher are synonyms defined as:

verifier and voucher: someone who vouches for another or for the correctness of a statement

verifier (noun)	voucher (noun)
someone who vouches for another or for the correctness of a statement	a negotiable certificate that can be detached and redeemed as needed
	a document that serves as evidence of some expenditure
	someone who vouches for another or for the correctness of a statement