game bird vs tinamou

game bird and tinamou both are nouns.

Word	Noun	Adjective	Verb	Adverb
game bird	Yes	No	No	No
tinamou	Yes	No	No	No

As nouns, tinamou is a hyponym of game bird; that is, tinamou is a word with a more specific, narrower meaning than game bird:

game bird: any bird (as grouse or pheasant) that is hunted for sport
tinamou: heavy-bodied small-winged South American game bird resembling a gallinaceous bird but related to the ratite birds

Other hyponyms of game bird include grouse, phasianid, partridge.

game bird (noun)	tinamou (noun)
any bird (as grouse or pheasant) that is hunted for sport	heavy-bodied small-winged South American game bird resembling a gallinaceous bird but related to the ratite birds