Source : Webster's Revised Unabridged Dictionary (1913)

Lasher \Lash"er\, n.
   One who whips or lashes.

Lasher \Lash"er\, n.
   1. A piece of rope for binding or making fast one thing to
      another; -- called also {lashing}.

   2. A weir in a river. [Eng.] --Halliwell.

Source : WordNet®

lasher
     n : a driver who urges the animals on with lashes of a whip