1. Vigilantly attentive; watchful: alert to danger; an alert bank guard. See synonyms at aware. 2. Mentally responsive and perceptive; quick. 3. Brisk or lively in action: the bird's alert hopping from branch to branch.
NOUN:
1. A signal that warns of attack or danger: Sirens sounded the alert for an air raid.2. A condition or period of heightened watchfulness or preparation for action: Nuclear-armed bombers were put on alert during the crisis.
TRANSITIVE VERB:
Inflected forms: a·lert·ed, a·lert·ing, a·lerts To notify of approaching danger or action; warn: a flashing red light that alerted motorists to trouble ahead.
IDIOM:
on the alert Watchful and prepared for danger, emergency, or opportunity: bird watchers on the alert for a rare species.
ETYMOLOGY:
French alerte, from Italian all' erta, on the lookout : alla, to the, on the (from Latin ad illam, to that ( ad, to; see ad– + illam, feminine accusative sing. of ille, that, the; see al-1 in Appendix I) + erta, lookout (from past participle of ergere, to raise, from Latin rigere; see erect).
-lûrt
rigere; see erect).
