A*lert" (#), a. [F. alerte, earlier a l'erte on the watch, fr. It. all' erta on the watch, prop. (standing) on a height, where one can look around; erta a declivity, steep, erto steep, p. p. of ergere, erigere, to erect, raise, L. erigere. See Erect.]
1.
Watchful; vigilant; active in vigilance.
2.
Brisk; nimble; moving with celerity.
An alert young fellow.
Addison.
Syn. -- Active; agile; lively; quick; prompt.
© Webster 1913.
A*lert", n. Mil.
An alarm from a real or threatened attack; a sudden attack; also, a bugle sound to give warning.
"We have had an
alert."
Farrow.
On the alert, on the lookout or watch against attack or danger; ready to act.
© Webster 1913.