fighter vs gamecock

fighter and gamecock both are nouns.

Word	Noun	Adjective	Verb	Adverb
fighter	Yes	No	No	No
gamecock	Yes	No	No	No

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

fighter (noun)	gamecock (noun)
a high-speed military or naval airplane designed to destroy enemy aircraft in the air	a cock bred and trained for fighting
someone who fights (or is fighting)	someone who is a very fierce fighter
someone who fights for a cause