voucher vs verifier

voucher and verifier both are nouns.

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

As nouns, voucher and verifier are synonyms defined as:

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

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