Roarer \Roar"er\, n.

1. One who, or that which, roars. Specifically:
   (a) A riotous fellow; a roaring boy.

A lady to turn roarer, and break glasses. --Massinger.
   (b) (Far.) A horse subject to roaring. See Roaring, 2.

2. (Zo["o]l.) The barn owl. [Prov. Eng.]

Source: Webster's Revised Unabridged Dictionary (1913)