Marder rhymes with:
ardor, carder, gaarder, harder, larder, yarder, ardor, boarder, border, camcorder, carder, corder, crossborder, dedeurwaerder, disorder, gaarder, gorder, harder, herder, larder, norder, order, recorder, reorder, snowboarder, vanorder, warder, weirder, yarder
Marder sounds like:
marauder, marter, martire, martyr, martyre, meridor, meritor, meriweather, meriwether, merriweather, merriwether, moratoria, mortar, mortara, morter, mortier, mortuary, muratore, murder, murderer