maintainer vs champion

maintainer and champion both are nouns.

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

As nouns, champion is a hypernym of maintainer; that is, champion is a word with a broader meaning than maintainer:

Other hypernyms of maintainer include admirer, booster, friend, protagonist, supporter.

maintainer (noun)	champion (noun)
someone who upholds or maintains	someone who fights for a cause
	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

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

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