/ kəmˈpʌlsəri; NAmE / adjective
that must be done because of a law or a rule
SYN mandatory :
It is compulsory for all motorcyclists to wear helmets.
English is a compulsory subject at this level.
compulsory education / schooling
compulsory redundancies
OPP voluntary
► com·pul·sor·ily / kəmˈpʌlsərəli; NAmE / adverb :
Over 600 workers were made compulsorily redundant.
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WORD ORIGIN
early 16th cent. (as a noun denoting a legal mandate which had to be obeyed): from medieval Latin compulsorius , from compuls- driven, forced, from the verb compellere , from com- together + pellere drive.