What is the meaning of Alert?

Attentive; awake; on guard.

brisk; nimble; moving with celerity.

An alarm.

A notification of higher importance than an advisory.

A state of readiness for potential combat.

To give warning to.

alert

alert

alert (device used to alarm people)

alert (sound used to alarm people)

alert (state of being alerted)

alert (state of readiness for potential combat)

alert

wide-awake

alert

Source: wiktionary.org