What is Suck-Out in Poker?

The term “Suck-Out” is commonly used when a player has very little equity in an hand but happens to get lucky and beat a much stronger hand. Also sometimes referred to as a Bad Beat. 

Example: Clarence has AA and the flop is A56. He goes all-in and his opponent Randy calls. Randy flips over 48, and is elated when the turn brings a 7, giving him the straight. The river is a brick and Clarence unhappily says “Way to suck-out on me, Randy!”