gaming vs gambling game

gaming and gambling game both are nouns.

Word	Noun	Adjective	Verb	Adverb
gaming	Yes	No	No	No
gambling game	Yes	No	No	No

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

gaming: the act of playing for stakes in the hope of winning (including the payment of a price for a chance to win a prize)
gambling game: a game that involves gambling

Other hyponyms of gaming include sporting life, bet, wager, game of chance, throw, retrogaming.

gaming (noun)	gambling game (noun)
the act of playing for stakes in the hope of winning (including the payment of a price for a chance to win a prize)	a game that involves gambling