im·per·a·tive / imˈperətiv/ • adj. 1. of vital importance; crucial: immediate action was imperative | it is imperative that standards be maintained. 2. giving an authoritative command; peremptory: the bell pealed again, a final imperative call. ∎ Gram. denoting the mood of a verb that expresses a command or exhortation, as in come here!• n. 1. an essential or urgent thing: free movement of labor was an economic imperative. ∎  a factor or influence making something necessary: the change came about through a financial imperative. ∎  a thing felt as an obligation: the moral imperative of aiding Third World development.2. Gram. a verb or phrase in the imperative mood. ∎  (the imperative) the imperative mood.DERIVATIVES: im·per·a·ti·val / -ˌperəˈtīvəl/ adj.im·per·a·tive·ly adv.im·per·a·tive·ness n.

IMPERATIVE. The MOOD of the VERB used to express commands (‘Go away’), requests (‘Please sit down’), warnings (‘Look out!’), offers (‘Have another piece’), and entreaties (‘Help me’). Sentences with an imperative as their main verb require the person(s) addressed to carry out some action. Hence, the subject of an imperative sentence is typically the second-person pronoun you, which is however normally omitted, as in ‘Go away’, but appears in the emphatic ‘You do as you're told!’ First- and third-person imperatives refer to the doer of the action or the requirement to perform the action less directly: ‘Let's go now’; ‘Someone close the window’.

imperative (gram.) expressing command; commanding, peremptory XVI; urgent XIX. — late L. imperātīvus, f. imperāt-, pp. stem of imperāre command (cf. EMPEROR); see -IVE.