finalist vs challenger

finalist and challenger both are nouns.

Word	Noun	Adjective	Verb	Adverb
finalist	Yes	No	No	No
challenger	Yes	No	No	No

As nouns, challenger is a hypernym of finalist; that is, challenger is a word with a broader meaning than finalist:

Other hypernyms of finalist include competition, competitor, contender, rival.

finalist (noun)	challenger (noun)
a contestant who reaches the final stages of a competition	the contestant you hope to defeat