Obligatory

adjective
ə'blɪɡə,toʊri

Adjective

  • morally or legally constraining or binding

    attendance is obligatory

    an obligatory contribution

    See also:Necessary
  • required by obligation or compulsion or convention

    he made all the obligatory apologies

Dictionary Validity

Tournament Word List (TWL)
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North American Scrabble (NWL2020)
NASPA