The Collaborative International Dictionary of English v.0.48:

Splasher \Splash"er\, n.
   1. One who, or that which, splashes.
      [1913 Webster]

   2. One of the guarde over the wheels, as of a carriage,
      locomotive, etc. --Weale.
      [1913 Webster]

   3. A guard to keep off splashes from anything.
      [1913 Webster]

WordNet (r) 3.0 (2006):

splasher
    n 1: a protective covering over or beside a wheel to protect the
         upper part of a vehicle from splashes of mud
    2: protective covering consisting of a panel to protect people
       from the splashing water or mud etc. [syn: splashboard,
       splasher, dashboard]