"to rove in quest of plunder, make an excursion for booty," especially of organized bands of soldiers, etc., 1711, from French marauder (17c.), from maraud "rascal" (15c.), a word of unknown origin, perhaps from French dialectal maraud "tomcat," echoic of its cry.
A word popularized in several languages during the Thirty Years' War (Spanish merodear, German marodiren, marodieren "to maraud," marodebruder "straggler, deserter") by punning association with Count Mérode, imperialist general. Related: Marauded; marauding.
<a href="https://www.etymonline.com/word/marauder">Etymology of marauder by etymonline</a>
Harper, D. (n.d.). Etymology of marauder. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/marauder