Idioms 1. Pool. b.
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.
Slang. an inept person.
behind the eightball, Informal. in a difficult, disadvantageous, or uncomfortable situation: He hasn't studied all term, and now he's behind the eightball.