The Collaborative International Dictionary of English v.0.48:

Bounder \Bound"er\ (bound"[~e]r), n.
   1. One who, or that which, limits; a boundary. --Sir T.
      Herbert.
      [1913 Webster]

   2. One who behaves dishonorably or objectionably; a cad.
      [PJC]

WordNet (r) 3.0 (2006):

bounder
    n 1: someone who is morally reprehensible; "you dirty dog" [syn:
         cad, bounder, blackguard, dog, hound, heel]
    2: someone who bounds or leaps (as in competition) [syn:
       bounder, leaper]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "bounder":
   Babbitt, Philistine, arriviste, boor, bourgeois, cad, churl, clown,
   cur, epicier, groundling, guttersnipe, hooligan, ill-bred fellow,
   looby, lout, low fellow, mucker, nouveau riche, parvenu, peasant,
   ribald, rotter, rough, roughneck, rowdy, ruffian, upstart,
   vulgarian, vulgarist, yokel