alert Meaning, Definition & Usage

  1. noun condition of heightened watchfulness or preparation for action
    qui vive.
    • bombers were put on alert during the crisis
  2. noun a warning serves to make you more alert to danger
    alerting.
  3. noun an automatic signal (usually a sound) warning of danger
    warning signal; alarm; alarum.
  4. verb warn or arouse to a sense of danger or call to a state of preparedness
    alarm.
    • The empty house alarmed him
    • We alerted the new neighbors to the high rate of burglaries
  5. adjective engaged in or accustomed to close observation
    watchful.
    • caught by a couple of alert cops
    • alert enough to spot the opportunity when it came
    • constantly alert and vigilant, like a sentinel on duty
  6. adjective satellite quick and energetic
    zippy; brisk; spanking; snappy; lively; merry; rattling.
    • a brisk walk in the park
    • a lively gait
    • a merry chase
    • traveling at a rattling rate
    • a snappy pace
    • a spanking breeze
  7. adjective satellite mentally perceptive and responsive
    awake; alive.
    • an alert mind
    • alert to the problems
    • alive to what is going on
    • awake to the dangers of her situation
    • was now awake to the reality of his predicament

WordNet

A*lert" adjective
Etymology
F. alerte, earlier à 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.
Definitions
  1. Watchful; vigilant; active in vigilance.
  2. Brisk; nimble; moving with celerity.
    An alert young fellow. Addison.
    Syn. -- Active; agile; lively; quick; prompt.
A*lert" noun
Definitions
  1. (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.

Webster 1913