voucher vs vouch

voucher is a noun but vouch is not a noun.

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

voucher (noun)	vouch (noun)
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

voucher (verb)	vouch (verb)
	give supporting evidence
	summon (a vouchee) into court to warrant or defend a title
	give personal assurance; guarantee
	give surety or assume responsibility