gambling vs card-playing

gambling is a noun but card-playing is not a noun.

Word	Noun	Adjective	Verb	Adverb
gambling	Yes	Yes	No	No
card-playing	No	Yes	No	No

As adjectives, gambling and card-playing are synonyms defined as:

gambling and card-playing: preoccupied with the pursuit of pleasure and especially games of chance

Other synonyms of gambling include betting, dissipated, sporting.

gambling (noun)	card-playing (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)

gambling (adjective)	card-playing (adjective)
preoccupied with the pursuit of pleasure and especially games of chance	preoccupied with the pursuit of pleasure and especially games of chance