crum·ple / ˈkrəmpəl/ • v. [tr.] crush (something, typically paper or cloth) so that it becomes creased and wrinkled. ∎ [intr.] become bent, crooked, or creased: they heard the jetliner crumple moments before it crashed. ∎ [intr.] (of a person) suddenly flop down to the ground so that their body appears bent or broken. ∎ [intr.] (of a person's face) suddenly sag and show an expression of desolation. ∎ [intr.] suddenly lose force or effectiveness: her composure crumpled.• n. a crushed fold, crease, or wrinkle.DERIVATIVES: crum·ply / ˈkrəmp(ə)lē/ adj.