WordWeb Online

1. Engaged in or accustomed to close observation
   "caught by a couple of watchful cops"
   - alert
    
2. Experiencing or accompanied by sleeplessness
   "twenty watchful, weary, tedious nights"
   - insomniac, sleepless

See also: argus-eyed, awake, fly [Brit], heads-up, lidless, lively, open-eyed, sleepless, vigilant, wakeful, wary, watchfully, watchfulness, wide-awake

Encyclopedia: Watchful