protagonist vs champion

protagonist and champion both are nouns.

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

As nouns, protagonist and champion are synonyms defined as:

protagonist and champion: a person who backs a politician or a team etc.

Other synonyms of protagonist include admirer, booster, friend, supporter.

protagonist (noun)	champion (noun)
a person who backs a politician or a team etc.	someone who fights for a cause
the principal character in a work of fiction	someone who has won first place in a competition
	a person who backs a politician or a team etc.
	someone who is dazzlingly skilled in any field

protagonist (adjective)	champion (adjective)
	holding first place in a contest

protagonist (verb)	champion (verb)
	protect or fight for as a champion