Russian roulette

WordReference Random House Unabridged Dictionary of American English © 2025

Rus′sian roulette′, 

1. a game of high risk in which each player in turn, using a revolver containing one bullet, spins the cylinder of the revolver, points the muzzle at the head, and pulls the trigger.

• 1935–40

Collins Concise English Dictionary © HarperCollins Publishers::

Russian roulette noun

1. a game of chance in which each player in turn spins the cylinder of a revolver loaded with only one cartridge and presses the trigger with the barrel against his or her own head
2. any act which, if repeated several times, is likely to have disastrous consequences