■ adjective
1》 of vital importance.
2》 giving an authoritative command.
↘ Grammar denoting the mood of a verb that expresses a command or exhortation, as in come here!
■ noun an essential or urgent thing.
↘a factor that makes something necessary.
Derivatives
imperatival ɪmˌpɛrə'tʌɪv(ə)l adjective
~ly adverb
~ness noun
Origin
ME: from late L. imperativus (lit. 'specially ordered'), from imperare 'to command', from in- 'towards' + parare 'make ready'.