Nouns

(n)adventure, escapade, risky venture, dangerous undertakinga wild and exciting undertaking (not necessarily lawful)

Verbs

(v)gamble, chance, risk, hazard, take chances, adventure, run a risk, take a chancetake a risk in the hope of a favorable outcome“When you buy these stocks you are gambling”
(v)venture, hazard, adventure, stake, jeopardizeput at risk“I will stake my good reputation for this”