adj. & n.
adj. 1 urgent. 2 obligatory. 3 commanding, peremptory. 4 Gram. (of a mood) expressing a command (e.g. come here!).
n. 1 Gram. the imperative mood. 2 a command. imperatival adj. imperatively adv. imperativeness n.
[ LL imperativus f. imperare command (as IN-(2), parare make ready) ]