From Longman Dictionary of Contemporary Englishalerta‧lert1 /əˈlɜːt $ -ɜːrt/ ●●○ adjective 1 INTELLIGENTgiving all your attention to what is happening, being said etc The animal raised its head, suddenly alert. Taking notes is one of the best ways to stay alert in lectures.2 able to think quickly and clearly Jack was as mentally alert as a man half his age.3 → be alert to something —alertness noun [uncountable]
Examples from the Corpus
alert• The men sit up, alert.• The medicine can make it difficult to remain alert.• But working in this sort of hospital you are always aware of the potential and you have to be alert.• Even many of the civilians in Charleston, which lay three miles across the bay from Sumter, were alert and anxious.• Being aware of this, you will be alert and attentive to meaning.• Passengers should try to stay alert at all times, and report any suspicious packages to the police immediately.• For a compulsively pensive person, to be fully alert but free of thought is a form of ecstasy...• an alert driver• She owes her life to an alert farmer, who spotted her car in a ditch and called the emergency services.• He listens with an alert, humorless expression.• The second effort was another wonderfully alert piece of rugby.stay alert• Blue gags on the image, tells himself to stay alert.• The men at the guns stayed alert.• They even set up a neat military system of two-man sentry duties, to make sure they stayed alert.• It was going to be another protracted day; he had to stay alert and miss nothing.• She sank deep down again, unable to stay alert, and saw without wanting to a giant Catherine-wheel in the sky.• You have to get it for yourself, by updating your skills constantly and staying alert to new opportunities.• As he retraced his steps of the past day avoiding streets and roads, he stayed alert to the sounds around him.mentally alert• Bernhardt stated that she continued to sculpt into old age to remain mentally alert.• This applies both to the mentally alert and the mentally confused.• Jamie Shepherd was well over eighty, yet he was as mentally alert as a man half his age.• So the old man went for the rye and champagne, and I mentally alerted my whistle to coming attractions.• I felt stimulated - mentally alert, talkative and sociable.• When I come away from working with Slatkin I always feel more mentally alert than when I started.alertalert2 ●●○ verb [transitive] 1 WARNto officially warn someone about a problem or danger so that they are ready to deal with it The school immediately alerted the police.► see thesaurus at warn2 SHOW/LET somebody SEE somethingto make someone realize something important or dangerousalert somebody to something campaigns to alert the public to the dangers of HIV→ See Verb tableExamples from the Corpus
alert• When he realized that one engine was not working, the pilot alerted air traffic control.• The perimeter was alerted, and most were awake.• But it was really quite useful, since it alerted his audience to stand by for something unexpected.• Some authors have suggested that the clicks are made to alert other cats to the presence of the prey.• When we find kids circumventing them, we alert our members and try to get the information out as quickly as possible.• a poster campaign to alert people to the disease• The sensors alerted police within seconds and, in some instances, placed the gunshots within 20 feet of their origin.• Drivers are being alerted that an escaped prisoner has been seen hitch-hiking on the road to Frankfurt.• One fireman alerted the residents and helped them to safety.• Echoes of the signal alert them to possible prey, at ranges up to 80-90 metres in shallow waters.alert somebody to something• A large sign alerts drivers to bad road conditions.alertalert3 noun 1 WARN[countable] a warning to be ready for possible dangera bomb/fire/terrorist etc alert a full-scale flood alert The bomb alert was raised soon after midnight. → red alert2 → on (the) alert (for something/somebody)Examples from the Corpus
alert• If we bypass the decision we simply move into autopilot and the red alert comes into play.• Read in studio A city centre is still sealed off following a security alert earlier this afternoon.• Because of the potential seriousness of the incident, a site alert was announced.• a smog alert• But there is manipulation in these alerts.• He lists a handful of false virus alerts and urban myths.a bomb/fire/terrorist etc alert• Several families were evacuated from their homes in Ulster last night after a bomb alert.• Then their wedding night in a luxury hotel was cut short at 6am - because of a fire alert.Origin alert1 (1500-1600) French alerte, from Italian all' erta “on the watch” 