imperative

adj. 1 urgent; obligatory. 2 commanding, peremptory. 3 gram. (of a mood) expressing a command (e.g. Come here!). n. 1 gram. Imperative mood. 2 command. 3 essential or urgent thing. [latin impero command]

a. Expressive of command; containing positive command; authoritatively or absolutely directive; commanding; authoritative; as, imperative orders.