adj. 1 sudden and unexpected; hasty (his abrupt departure). 2 (of speech, manner, etc.) uneven; lacking continuity; curt. 3 steep, precipitous. 4 Bot. truncated. 5 Geol. (of strata) suddenly appearing at the surface. abruptly adv. abruptness n.
[ L abruptus past part. of abrumpere (as AB-, rumpere break) ]