eightball

[eyt-bawl]
noun
  1. Pool.
    1. a black ball bearing the number eight.
    2. a game in which one player or side must pocket all of either the solid-color balls or the striped ones before being permitted to attempt the pocketing of the eightball, which wins.
  2. Slang. an inept person.
Idioms
  1. behind the eightball, Informal. in a difficult, disadvantageous, or uncomfortable situation: He hasn't studied all term, and now he's behind the eightball.

Origin of eightball

An Americanism dating back to 1930–35; eight + ball1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018