WordWeb Online

1. Exceptionally bad or displeasing
   "terrible handwriting";
   - atrocious, abominable, awful, dreadful, painful, unspeakable, horrible
    
2. Causing fear, dread or terror
   "a terrible curse";
   - awful, dire, direful, dread, dreaded, dreadful, fearful, fearsome, frightening, horrendous, horrific
    
3. Intensely or extremely bad or unpleasant in degree or quality
   "a terrible cough";
   - severe, wicked [informal]
    
4. Extreme in degree, extent, amount or impact
   "in a terrible hurry";
   - frightful, awful, tremendous

See also: alarming, bad, extraordinary, intense

Encyclopedia: Terrible