Being in compliance with the law; lawful: a legitimate business. Being in accordance with established or accepted rules and standards: legitimate advertising practices. Valid or justifiable: a legitimate complaint. Based on logical reasoning: a legitimate deduction. Born of legally married parents: legitimate offspring. Of, relating to, or ruling by hereditary right: a legitimate monarch. Of or relating to drama of high professional quality that excludes burlesque, vaudeville, and some forms of musical comedy: the legitimate theater.