Synonyms of 'compulsory'

absolute, binding, coactive, compelling, compulsive, conclusive, decisive, decretory, driving, exigent, final, hard-and-fast, imperative, imperious, importunate, inevitable, involuntary, irresistible, irrevocable, mandatory, must, necessary, necessitous, obligatory, peremptory, prescript, prescriptive, pressing, ultimate, urgent