perfect game vs baseball

perfect game and baseball both are nouns.

Word	Noun	Adjective	Verb	Adverb
perfect game	Yes	No	No	No
baseball	Yes	No	No	No

As nouns, baseball is a hypernym of perfect game; that is, baseball is a word with a broader meaning than perfect game:

perfect game: a game in which a pitcher does not allow any opposing player to reach base
baseball: a ball game played with a bat and ball between two teams of nine players; teams take turns at bat trying to score runs

Other hypernyms of perfect game include ball, baseball game.

perfect game (noun)	baseball (noun)
a game in which a pitcher does not allow any opposing player to reach base	a ball game played with a bat and ball between two teams of nine players; teams take turns at bat trying to score runs
	a ball used in playing baseball