Ride roughshod over is an idiom which means to treat someone or something harshly and without regard for their feelings. DOMINEER, with 8 letters, is a verb meaning to exercise power over someone in a cruel and oppressive way. Illtreat, also with 8 letters, is a verb meaning to treat someone cruelly or unfairly. Together, these three words describe the act of treating someone or something harshly and without regard for their feelings, while exercising power over them in a cruel and oppressive way.