WordWeb Online

1. Marked by sudden changes in subject and sharp transitions
   "abrupt prose"
   - disconnected
    
2. Exceedingly sudden and unexpected
   "came to an abrupt stop"; "an abrupt change in the weather"
    
3. Extremely steep
   "an abrupt canyon"
   - precipitous, sharp
    
4. Surprisingly and unceremoniously brusque in manner
   "an abrupt reply"

Derived forms: abruptest, abrupter

See also: abruptly, abruptness, disconnected, discourteous, staccato, steep, sudden