The Collaborative International Dictionary of English v.0.48:

Marauder \Ma*raud`er\, n. [From Maraud, v.: cf. F. maraudeur.]
   A rover in quest of booty or plunder; a plunderer; one who
   pillages. --De Quincey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

marauder
    n 1: someone who attacks in search of booty [syn: marauder,
         predator, vulture, piranha]