Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Vigilantly attentive; watchful: alert to danger; an alert bank guard. See Synonyms at aware.
  • adj. Mentally responsive and perceptive; quick.
  • adj. Brisk or lively in action: the bird's alert hopping from branch to branch.
  • n. A signal that warns of attack or danger: Sirens sounded the alert for an air raid.
  • n. A condition or period of heightened watchfulness or preparation for action: Nuclear-armed bombers were put on alert during the crisis.
  • transitive v. 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Attentive; awake; on-guard.
  • n. An alarm.
  • n. A notification of higher importance than an advisory.
  • v. To give warning to.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Watchful; vigilant; active in vigilance.
  • adj. Brisk; nimble; moving with celerity.
  • n. An alarm from a real or threatened attack; a sudden attack; also, a bugle sound to give warning.

from The Century Dictionary and Cyclopedia

  • Active in vigilance; watchful; vigilantly attentive.
  • Moving with celerity; brisk; active; nimble: as, “an alert young fellow,” Addison, Spectator, No. 403.
  • Lively, agile, quick, prompt, ready, spry.
  • n. An attitude of vigilance; watch; guard: especially in the phrase on or upon the alert, upon the watch; on the lookout; guarding against surprise or danger: as, “the readiness of one on the alert,” Dickens.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. engaged in or accustomed to close observation
  • adj. mentally perceptive and responsive
  • v. warn or arouse to a sense of danger or call to a state of preparedness
  • adj. quick and energetic
  • n. a warning serves to make you more alert to danger
  • n. condition of heightened watchfulness or preparation for action
  • n. an automatic signal (usually a sound) warning of danger

Etymologies

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.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From French alerte ("alert"), from the phrase à l'erte ("on the watch"), from Italian all'erta ("to the height"), from erta ("lookout, tower"). (Wiktionary)

Examples

Comments

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  • Should I also be amoral because the world needs more morals?

    March 25, 2009

  • Be alert. The world needs more lerts.

    March 25, 2009

  • "Communities in Healesville, Chum Creek, Badger Creek, Steels Creek, Dixons Creek, Yarra Glen, Toolangi and Castello are being advised to remain alert to fire activity."
    - CFA urges vigilance despite 'calming' threat, abc.net.au, 11 Feb 2009.

    Correction: although this quote says Castello, the hamlet's name is Castella. I learned this in high school when I was stopping people in the street to do a survey of their shopping habits.

    February 12, 2009