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
3.
behind the eightball, Informal. in a difficult, disadvantageous, or uncomfortable situation:
He hasn't studied all term, and now he's behind the eightball.