contestant vs CO

contestant and CO both are nouns.

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

As nouns, CO is a hyponym of contestant; that is, CO is a word with a more specific, narrower meaning than contestant:

Other hyponyms of contestant include conscientious objector, nonconformist, recusant, political dissident, NIMBY.

contestant (noun)	CO (noun)
a person who participates in competitions	a state in west central United States in the Rocky Mountains
a person who dissents from some established policy	one who refuses to serve in the armed forces on grounds of conscience
	an odorless very poisonous gas that is a product of incomplete combustion of carbon