voucher vs protagonist

voucher and protagonist both are nouns.

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

As nouns, protagonist is a hypernym of voucher; that is, protagonist is a word with a broader meaning than voucher:

voucher: someone who vouches for another or for the correctness of a statement
protagonist: a person who backs a politician or a team etc.

Other hypernyms of voucher include admirer, booster, champion, friend, supporter.

voucher (noun)	protagonist (noun)
a negotiable certificate that can be detached and redeemed as needed	a person who backs a politician or a team etc.
a document that serves as evidence of some expenditure	the principal character in a work of fiction
someone who vouches for another or for the correctness of a statement