adj. 25B6; adjective
an abrupt halt 007C; an abrupt change of subject : SUDDEN, unexpected, without warning, unanticipated, unforeseen, precipitate, surprising, startling; quick, swift, rapid, hurried, hasty, immediate, instantaneous.
an abrupt manner : CURT, brusque, blunt, short, sharp, terse, brisk, crisp, gruff, rude, discourteous, uncivil, snappish, unceremonious, offhand, rough, harsh; bluff, no-nonsense, to the point; informal snappy.
abrupt, epigrammatic paragraphs : DISJOINTED, jerky, uneven, disconnected, inelegant.
an abrupt slope : STEEP, sheer, precipitous, bluff, sharp, sudden; perpendicular, vertical, dizzy, vertiginous.
gradual, gentle.