The Collaborative International Dictionary of English v.0.48:
Plunderer \Plun"der*er\, n. One who plunders or pillages. [1913 Webster]WordNet (r) 3.0 (2006):
plunderer n 1: someone who takes spoils or plunder (as in war) [syn: plunderer, pillager, looter, spoiler, despoiler, raider, freebooter]