The Collaborative International Dictionary of English v.0.48:

despoilment \de*spoil"ment\, n.
   Despoliation. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

despoilment
    n 1: the act of stripping and taking by force [syn: spoil,
         spoliation, spoilation, despoilation, despoilment,
         despoliation]