An essential action, a must: something which is imperative.
A verb in imperative mood.
The grammatical mood expressing an order (see jussive). In English, the imperative form of a verb is the same as that of the bare infinitive.
Having semantics that incorporates mutable variables.
Expressing a command; authoritatively or absolutely directive.
Essential; crucial; extremely important.
Of, or relating to the imperative mood.
Something that is required as necessary or indispensable, or as a prior condition of something else.
In education, a course or topic that must be completed before another course or topic can be started. May be colloquially referred to as a prereq.
Required as a prior condition of something else; necessary or indispensable.