competitor vs contender

competitor and contender both are nouns.

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

As nouns, competitor and contender are synonyms defined as:

Other synonyms of competitor include challenger, competition, rival.

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