champion vs endorse

champion is a noun but endorse is not a noun.

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

As verbs, endorse is a hypernym of champion; that is, endorse is a word with a broader meaning than champion:

Other hypernyms of champion include back, indorse, plump for, plunk for, support.

champion (noun)	endorse (noun)
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

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

champion (verb)	endorse (verb)
protect or fight for as a champion	sign as evidence of legal transfer
	be behind; approve of
	guarantee as meeting a certain standard
	give support or one's approval to