Booty: property necessary and indispensable for the conduct of war (eg, food, transportation, communication)
Pillage, or plunder: the taking of private property not necessary for the immediate prosecution of the war effort (eg, Marc Chagall painting taken by the Nazis).
Menzel v. List, 49 Misc. 2d 300 (NY 1966).
The plaintiffs fled their home ahead of the Nazis. The weird part is that when they returned 6 years later, the German authorities had left a receipt for the painting.
In the end, the plaintiff got her painting back, and the gallery got the present value of the work ($22,500) from the person from whom they'd bought the painting (for $4,000).