champion vs friend

champion and friend both are nouns.

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

As nouns, champion and friend are synonyms defined as:

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

champion (noun)	friend (noun)
someone who fights for a cause	a person you know well and regard with affection and trust
someone who has won first place in a competition	a person with whom you are acquainted
a person who backs a politician or a team etc.	an associate who provides cooperation or assistance
someone who is dazzlingly skilled in any field	a person who backs a politician or a team etc.

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

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