The Collaborative International Dictionary of English v.0.48:

Bludgeon \Bludg"eon\, n. [Cf. Ir. blocan a little block, Gael.
   plocan a mallet, W. plocyn, dim. of ploc block; or perh.
   connected with E. blow a stroke. Cf. Block, Blow a
   stroke.]
   A short stick, with one end loaded, or thicker and heavier
   that the other, used as an offensive weapon.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bludgeon
    n 1: a club used as a weapon
    v 1: overcome or coerce as if by using a heavy club; "The
         teacher bludgeoned the students into learning the math
         formulas"
    2: strike with a club or a bludgeon [syn: club, bludgeon]