Answer: MANDATORY

AnswerCrossword Clue
MANDATORYImperative
MANDATORYRequired
MANDATORYRequired.
MANDATORYImperative.
MANDATORYBinding
mandatoryOf or conveying a command
mandatoryby mandate also MANDATARY / the holder of a mandate
mandatoryRequired by law or rules; compulsory