imperative

(grammar) 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.

“The verbs in sentences like "Do it!" and "Say what you like!" are in the imperative.”

(grammar) A verb in imperative mood.

An essential action, a must: something which is imperative.

“Visiting Berlin is an imperative.”

Essential; crucial; extremely important.

“It is imperative that you come here right now.”

(grammar) Of, or relating to the imperative mood.

Having semantics that incorporates mutable variables.

Expressing a command; authoritatively or absolutely directive.

“imperative orders”