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behind the eight ball

Meaning 1
The player must knock all numbered balls from one to seven into the pocket before the eighth ball.
Sentence 1
The six ball was behind the eight ball and it was a difficult shot.
Meaning 2
to be in a difficult or awkward situation
Sentence 2
I was behind the eight ball when the boss found out I didn't know any foreign languages.

Derivation

It is very difficult to make a shot with a ball, if that ball is directly behind the eight ball.