run a risk vs gamble

run a risk is not a noun while gamble is a noun.

Word	Noun	Adjective	Verb	Adverb
run a risk	No	No	Yes	No
gamble	Yes	No	Yes	No

As verbs, run a risk and gamble are synonyms defined as:

Other synonyms of run a risk include adventure, chance, hazard, risk, take a chance, take chances.

run a risk (noun)	gamble (noun)
	a risky act or venture
	money that is risked for possible monetary gain

run a risk (verb)	gamble (verb)
take a risk in the hope of a favorable outcome	play games for money
	take a risk in the hope of a favorable outcome