1. A potentially fatal game of chance involving a revolver loaded with a single bullet, in which each participant in turn spins the cylinder so that the bullet's location is unknown, puts the barrel to their head, and pulls the trigger. A student of the university died over the weekend after apparently playing a game of Russian roulette with other members of his fraternity.

2. By extension, any reckless, foolish, and/or dangerous act or stunt, especially that in which the risk of danger or trouble is increased with the number of times one does it. Your company might have passed its audit this year, Mr. Fisk, but every year is going to be Russian roulette so long as this embezzlement continues. You're playing Russian roulette every single time you get behind the wheel of a car when you've been drinking.