Attentive; awake; on guard. / (obsolete) brisk; nimble; moving with celerity.

An alarm. / A notification of higher importance than an advisory. / (military) A state of readiness for potential combat.

To give warning to.

The quality of being alert or on the alert

plural of alert

Third-person singular simple present indicative form of alert

present participle of alert

simple past tense and past participle of alert

Having been made alert; having been made attentive, alarmed or warned of something coming soon.

One who or that which alerts.