opposition vs contestant

opposition and contestant both are nouns.

Word	Noun	Adjective	Verb	Adverb
opposition	Yes	No	No	No
contestant	Yes	No	No	No

As nouns, contestant is a hypernym of opposition; that is, contestant is a word with a broader meaning than opposition:

opposition (noun)	contestant (noun)
the act of hostile groups opposing each other	a person who participates in competitions
the action of opposing something that you disapprove or disagree with	a person who dissents from some established policy
a body of people united in opposing something
an armed adversary (especially a member of an opposing military force)
a contestant that you are matched against
a direction opposite to another
the relation between opposed entities