Source : Webster's Revised Unabridged Dictionary (1913)

Drowsy \Drow"sy\, a. [Compar. {Drowsier}; superl. {Drowsiest}.]
   1. Inclined to drowse; heavy with sleepiness; lethargic;
      dozy. ``When I am drowsy.'' --Shak.

            Dapples the drowsy east with spots of gray. --Shak.

            To our age's drowsy blood Still shouts the inspiring
            sea.                                  --Lowell.

   2. Disposing to sleep; lulling; soporific.

            The drowsy hours, dispensers of all good.
                                                  --Tennyson.

   3. Dull; stupid. `` Drowsy reasoning.'' --Atterbury.

   Syn: Sleepy; lethargic; dozy; somnolent; comatose; dull
        heavy; stupid.

Source : WordNet®

drowsy
     adj 1: half asleep; "made drowsy by the long ride"; "it seemed a
            pity to disturb the drowsing (or dozing) professor";
            "a tired dozy child"; "the nodding (or napping)
            grandmother in her rocking chair" [syn: {drowsing(a)},
             {dozy}]
     2: showing lack of attention or boredom; "the yawning
        congregation" [syn: {oscitant}, {yawning(a)}]
     [also: {drowsiest}, {drowsier}]