An Etymological Dictionary of the German Language/Annotated/Plunder
Plunder, masculine, ‘trash, lumber, plunder,’ from late Middle High German plunder, blunder, masculine, ‘household furniture, clothes, linen,’ which is probably a Low German loan-word (Middle Low German plunde, ‘clothing’). Hence plündern, ‘to plunder,’ literally ‘to take away the household furniture’ (also Dutch plunderen, ‘to plunder’).