Behind the eight ball

To get behind the eight ball is to be in a difficult position from which it is well nigh impossible to escape. The expression is American and dates from the early 20th century. It derives from the table game of Pool, an American form of snooker or billiards, where the balls are numbered. The number eight ball is the black one that must be potted i.e. propelled into a pocket as the last ball in the game. Players forfeit a turn if the cue ball strikes the black eight ball. They forfeit the game if they inadvertently pot this ball before it becomes the last ball. If one’s cue ball is directly behind the eight ball and therefore likely to strike it, a player is in a very difficult position.