croupier vs gambler

croupier and gambler both are nouns.

Word	Noun	Adjective	Verb	Adverb
croupier	Yes	No	No	No
gambler	Yes	No	No	No

As nouns, gambler is a hypernym of croupier; that is, gambler is a word with a broader meaning than croupier:

croupier: someone who collects and pays bets at a gaming table
gambler: a person who wagers money on the outcome of games or sporting events

croupier (noun)	gambler (noun)
someone who collects and pays bets at a gaming table	a person who wagers money on the outcome of games or sporting events
	someone who risks loss or injury in the hope of gain or excitement