- fully aware and attentive; wide-awake; keen: an alert mind.
- swift; agile; nimble.
- an attitude of vigilance, readiness, or caution, as before an expected attack.
- a warning or alarm of an impending military attack, a storm, etc.: We'd just boarded the bus when the alert sounded.
- the period during which such a warning or alarm is in effect.
- to warn (troops, ships, etc.) to prepare for action.
- to warn of an impending raid, attack, storm, etc.: The radio alerted coastal residents to prepare for the hurricane.
- to advise or warn; cause to be on guard: to alert gardeners to the dangers of some pesticides.
- on the alert, on guard against danger; in readiness; vigilant: The state police are on the alert for an escaped convict believed to be in the area.
Origin of alert
SynonymsSee more synonyms on Thesaurus.com
Examples from the Web for alert
Minutes before an airplane hit the water, an alert would go out.Red Tape and Black Boxes: Why We Keep ‘Losing’ Airliners in 2014
December 29, 2014
I also want to alert you to the broader circumstances of my incarceration.An American Marine in Iran’s Prisons Goes on Hunger Strike
December 18, 2014
They walk closely together, tense, and alert in their movements.‘Girlhood’: Coming of Age in France’s Projects
November 25, 2014
Most people are expected to self-monitor and alert authorities if their temperature rises.Europe’s Hidden Ebola Cases
Barbie Latza Nadeau
October 15, 2014
If someone finds a great spot to set up camp miles away, they can alert friends from other groups.London’s Pagan Counterculture Kings
October 12, 2014
The strong man must at all times be alert to the attack of insidious disease.
And accordingly, when he wakened in the middle of the night, he was alert on the instant.Way of the Lawless
He moved with alert assurance, lithely balanced on the balls of his feet, noiselessly.
Instantly, he was all alert to meet the exigencies of the situation.
With narrow, alert eyes, Linda was watching, and her brain was keenly alive.Her Father's Daughter
- vigilantly attentivealert to the problems
- brisk, nimble, or lively
- an alarm or warning, esp a siren warning of an air raid
- the period during which such a warning remains in effect
- on the alert
- on guard against danger, attack, etc
- watchful; readyon the alert for any errors
- to warn or signal (troops, police, etc) to prepare for action
- to warn of danger, an attack, etc
Word Origin and History for alert
"on the watch," 1590s, from French alerte "vigilant" (17c.), from phrase à l'erte "on the watch," from Italian all'erta "to the height," from erta "lookout, high tower," noun use of fem. of erto, past participle of ergere "raise up," from Latin erigere "raise" (see erect). The adjective is attested from 1610s, the noun from 1803, and the verb from 1868. Related: Alerted; alerting.
Idioms and Phrases with alert
see on the alert.