The Collaborative International Dictionary of English v.0.48:

Defaulter \De*fault"er\, n.
   1. One who makes default; one who fails to appear in court
      when court when called.
      [1913 Webster]

   2. One who fails to perform a duty; a delinquent;
      particularly, one who fails to account for public money
      intrusted to his care; a peculator; a defalcator.
      [1913 Webster]

WordNet (r) 3.0 (2006):

defaulter
    n 1: someone who fails to make a required appearance in court
    2: someone who fails to meet a financial obligation [syn:
       defaulter, deadbeat]
    3: a contestant who forfeits a match

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DEFAULTER, com. law. One who is deficient in his accounts, or falls in
making his accounts correct.