competitor vs challenger

competitor and challenger both are nouns.

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

As nouns, competitor and challenger are synonyms defined as:

Other synonyms of competitor include competition, contender, rival.

competitor (noun)	challenger (noun)
the contestant you hope to defeat	the contestant you hope to defeat