gambling vs wager

gambling and wager both are nouns.

Word	Noun	Adjective	Verb	Adverb
gambling	Yes	Yes	No	No
wager	Yes	No	Yes	No

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

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

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

gambling (noun)	wager (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)	the act of gambling
	the money risked on a gamble

gambling (adjective)	wager (adjective)
preoccupied with the pursuit of pleasure and especially games of chance

gambling (verb)	wager (verb)
	maintain with or as if with a bet
	stake on the outcome of an issue