The Collaborative International Dictionary of English v.0.48:

Bouncer \Boun"cer\, n.
   1. One who bounces; a large, heavy person who makes much
      noise in moving.
      [1913 Webster]

   2. A boaster; a bully. [Collog.] --Johnson.
      [1913 Webster]

   3. A bold lie; also, a liar. [Collog.] --Marryat.
      [1913 Webster]

   4. Something big; a good stout example of the kind.
      [1913 Webster]

            The stone must be a bouncer.          --De Quincey.
      [1913 Webster]

   5. a person employed by a tavern, nightclub, or other place
      of public meeting, to eject persons who become violent or
      unruly.
      [PJC]

WordNet (r) 3.0 (2006):

bouncer
    n 1: a person whose duty is to throw troublemakers out of a bar
         or public meeting [syn: bouncer, chucker-out]