Source : Webster's Revised Unabridged Dictionary (1913)

Rouser \Rous"er\, n.
   1. One who, or that which, rouses.

   2. Something very exciting or great. [Colloq.]

   3. (Brewing) A stirrer in a copper for boiling wort.

Source : WordNet®

rouser
     n : someone who rouses others from sleep [syn: {waker}, {arouser}]