A marauder is someone who roams around looking for things to steal. You might hear news reports about a marauder breaking into cars in your neighborhood.
The word marauder entered English in the 17th century, from the Middle French word maraud, meaning "rascal." Even in modern times, if you’re a marauder you’re certainly a rascal — probably even a criminal. A marauder doesn’t target a victim and plan a crime — instead a marauder is on the move looking for opportunities to rob people or steal things. Marauders often travel in groups, looting whatever they can.