Antonyms for mandatory

required, necessary:

free, optional, unforced, voluntary, unnecessary, nonessential, secondary, inessential.

noun:

elective, inconsequential, insignificant, nonessential, unwanted, dispensable, unneeded, unimportant, chosen, unnecessary.

Paraphrases for Mandatory:

• Adjective :
  absolute, accountable, arbitrary, authentic, authoritative, automated, automatic, basic, binding, bounden, burdensome, categorical, coerce, Coerced, coercive, committed, compelling, compensatory, compulsory, conclusive, consistent, constituent, constitutional, constraining, critical, crucial, cumbersome, D, definite, demanding, demands, discretionary, due, duty, duty-bound, element, enforced, Envisaged, essential, established, ex-officio, Executable, Executory, fascicle, firm, fixed, forced, forceful, Forcing, formal, formidable, generate, Generating, godown, honorary, ideal, imperative, imposed, imposing, incumbent, indispensable, indisputable, ineluctable, inescapable, inevitable, key, lawful, legally-binding, liable, main, mandate, mandated, minimal, minimum, much-needed, needed, non-binding, non-compensatory, non-compulsory, non-derogable, non-discretionary, non-mandatory, obligate, obligated, obligatory, oblige, onerous, operative, optional, overarching, overriding, paramount, parliamentary, payable, peremptory, powerful, prescribed, prescriptive, present, pressing, produce, Producing, regulated, regulation-making, regulatory, reportable, require, required, requirement, Requiring, requisite, responsible, restrictive, rigid, rigorous, rigour, routine, shall, specific, specified, starting, statutory, Stipulated, stipulates, strict, stringency, stringent, strong, subject, systematic, systemic, tight, tough, unavoidable, undeniable, universal, unshirkable, urgent, valid, vital.
• Adverb :
  compulsorily, compulsory, necessarily.
• Cardinal number :
  compulsory.
• Determiner :
  all, an, compulsory, obligatory, statutory.
• Noun, plural :
  Duties, duty, obligations, obligatory, requirements.
• Noun, singular or mass :
  'obligation, assessment, attendance, binding, coercion, coercive, compulsion, compulsory, condition, conscription, constraint, duty, enforcement, imperative, imposition, information, instrument, law, Les, minimum, non-compensatory, non-mandatory, obligation, obligatory, onus, regulatory, representation, required, requirement, statutory, use.
• Proper noun, singular :
  binding, coercive, compulsory, Duties, duty, enforced, enforcement, eng-kiong, fixed, forced, imperative, keung, Les, mandate, mandated, minimum, MPF, must, obligation, obligations, obligatory, powers, qiang, representation, required, requirement, requirements, rules, statutory, wai-keung.
• Verb, 3rd person singular present :
  includes, needs, requires.
• Verb, past tense :
  mandated, required, Stipulated.