Meaning 1 ►▼
The player must knock all numbered balls from one to seven into the pocket before the eighth ball.
The six ball was behind the eight ball and it was a difficult shot.
Meaning 2 ►▼
to be in a difficult or awkward situation
I was behind the eight ball when the boss found out I didn't know any foreign languages.
It is very difficult to make a shot with a ball, if that ball is directly behind the eight ball.