very urgent or important; not to be avoided
It is our imperative duty to stop the killing
commanding; showing authority
expressive of a command, entreaty, or exhortation
having the power to restrain, control, and direct
relating to or denoting the grammatical mood that expresses command, e.g. the verb stop in Stop that at once!
imperatively adv
imperativeness noun
[late Latin imperativus, from Latin imperare to command, from in-2 + parare to make ready]