alert

/əˈlɜːt/
/əˈlɝt/
/əˈlɝt/

noun

  1. An alarm.

  2. A notification of higher importance than an advisory.

  3. A state of readiness for potential combat.

    "an airborne alert; ground alert"

adjective

  1. Attentive; awake; on guard.

  2. Brisk; nimble; moving with celerity.

verb

  1. To give warning to.