imperative
adj 1: requiring attention or action; "as nuclear weapons
proliferate, preventing war becomes imperative";
"requests that grew more and more imperative" [ant: {beseeching}]
2: (grammar) relating to verbs in the imperative mood
n 1: a mood that expresses an intention to influence the
listener's behavior [syn: {imperative mood}, {jussive
mood}]
2: some duty that is essential and urgent