The Collaborative International Dictionary of English v.0.48:

Flasher \Flash"er\, n.
   1. One who, or that which, flashes.
      [1913 Webster]

   2. A man of more appearance of wit than reality.
      [1913 Webster]

   3. (Zool.)
      (a) A large sparoid fish of the Atlantic coast and all
          tropical seas (Lobotes Surinamensis).
      (b) The European red-backed shrike (Lanius collurio); --
          called also flusher.
          [1913 Webster]

   4. An exhibitionist[1], especially a male, who briefly
      exposes his private parts in a public place.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Flusher \Flush"er\, n.
   1. A workman employed in cleaning sewers by flushing them
      with water.
      [1913 Webster]

   2. (Zool.) The red-backed shrike. See Flasher.
      [1913 Webster]