WordWeb Online

1. Having or revealing stupidity
   "ridiculous dopy behaviour";
   - anserine, dopey, foolish, goosey, goosy, gooselike, jerky
    
2. Showing lack of attention or boredom
   "the dopy congregation";
   - drowsy, oscitant, yawning, dopey
    
3. Half asleep
   "it seemed a pity to disturb the dopy professor";
   - drowsy, drowsing, dozy, dopey

See also: asleep, inattentive, sleeping, stupid, unattentive [rare]