fully aware and attentive; wide-awake; keen: an alert mind.
swift; agile; nimble.
noun
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.
verb (used with object)
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.
Idioms for alert
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
1590–1600; 1940–45 for def. 4; <Italian all'erta, equivalent to all(a) to, on the + erta lookout, watchtower, originally feminine of erto, past participle of ergere<Latin ērigere to erect
1. Alert,vigilant,watchful imply a wide-awake attitude, as of someone keenly aware of his or her surroundings. Alert describes a ready and prompt attentiveness together with a quick intelligence: The tourist was alert and eager to see the sights.Vigilant suggests some immediate necessity for keen, active observation, and for continuing alertness: Knowing the danger, the scout was unceasingly vigilant.Watchful suggests carefulness and preparedness: watchful waiting.
The US Federal Bureau of Investigation became involved early on when the Tesla employee alerted it to Kriuchkov’s plan.
How a $1 million plot to hack Tesla failed|Patrick O'Neill|August 28, 2020|MIT Technology Review
There's also an app—of course there's an app—that will alert you when the mask filters need to be replaced.
LG’s battery-powered face mask will “make breathing effortless”|Ron Amadeo|August 27, 2020|Ars Technica
The new $100 Inspire 2 activity tracker is different from the Halo, however, with a small screen that provides phone notifications and app alerts.
Amazon jumps into smart wearables market with Halo activity tracking band|Aaron Pressman|August 27, 2020|Fortune
Mobile phone and broadcast alerts advised people to prepare to evacuate.
Improved three-week weather forecasts could save lives from disaster|Alexandra Witze|August 27, 2020|Science News
District Attorney Michael Ramsey of Butte County, where Paradise is located, confirmed in March that PG&E alerted his office to the allegations and said he was awaiting further information.
The Mystery House: How a Suspicious Multimillion Dollar Real Estate Deal Is Connected to California’s Deadliest Fire|by Scott Morris, Bay City News Foundation|August 26, 2020|ProPublica
Minutes before an airplane hit the water, an alert would go out.
Red Tape and Black Boxes: Why We Keep ‘Losing’ Airliners in 2014|Clive Irving|December 29, 2014|DAILY BEAST
I also want to alert you to the broader circumstances of my incarceration.
An American Marine in Iran’s Prisons Goes on Hunger Strike|IranWire|December 18, 2014|DAILY BEAST
They walk closely together, tense, and alert in their movements.
‘Girlhood’: Coming of Age in France’s Projects|Molly Hannon|November 25, 2014|DAILY BEAST
Most people are expected to self-monitor and alert authorities if their temperature rises.