Source : Webster's Revised Unabridged Dictionary (1913)

Abrupt \Ab*rupt"\, a. [L. abruptus, p. p. of abrumpere to break
   off; ab + rumpere to break. See {Rupture}.]
   1. Broken off; very steep, or craggy, as rocks, precipices,
      banks; precipitous; steep; as, abrupt places. ``Tumbling
      through ricks abrupt,'' --Thomson.

   2. Without notice to prepare the mind for the event; sudden;
      hasty; unceremonious. ``The cause of your abrupt
      departure.'' --Shak.

   3. Having sudden transitions from one subject to another;
      unconnected.

            The abrupt style, which hath many breaches. --B.
                                                  Jonson.

Abrupt \Ab*rupt"\, n. [L. abruptum.]
   An abrupt place. [Poetic]

         ``Over the vast abrupt.''                --Milton.

Abrupt \Ab*rupt"\, v. t.
   To tear off or asunder. [Obs.] ``Till death abrupts them.''
   --Sir T. Browne.

Source : WordNet®

abrupt
     adj 1: marked by sudden changes in subject and sharp transitions;
            "abrupt prose" [syn: {disconnected}]
     2: exceedingly sudden and unexpected; "came to an abrupt stop";
        "an abrupt change in the weather"
     3: extremely steep; "an abrupt canyon"; "the precipitous rapids
        of the upper river"; "the precipitous hills of Chinese
        paintings"; "a sharp drop" [syn: {precipitous}, {sharp}]
     4: surprisingly and unceremoniously brusque in manner; "an
        abrupt reply"