imperative: Meaning and Definition of

im•per•a•tive

1. absolutely necessary or required; unavoidable: It is imperative that we leave.
2. of the nature of or expressing a command; commanding.
3. noting or pertaining to the mood of the verb used in commands, requests, etc., as in Listen! Go! Cf. indicative (def. 2),(def. 1).

1. a command.
2. something that demands attention or action; an unavoidable obligation or requirement; necessity: It is an imperative that we help defend friendly nations.
1. the imperative mood.
2. a verb in this mood.
4. an obligatory statement, principle, or the like.