game room vs rumpus room

game room and rumpus room both are nouns.

Word	Noun	Adjective	Verb	Adverb
game room	Yes	No	No	No
rumpus room	Yes	No	No	No

As nouns, game room and rumpus room are synonyms defined as:

game room and rumpus room: a recreation room for noisy activities (parties or children's play etc)

Other synonyms of game room include playroom.

game room (noun)	rumpus room (noun)
a recreation room for noisy activities (parties or children's play etc)	a recreation room for noisy activities (parties or children's play etc)