Meaning of ALERT in English


I. a ‧ lert 1 /əˈlɜːt $ -ɜːrt/ BrE AmE adjective

[ Date: 1500-1600 ; Language: French ; Origin: alerte , from Italian all' erta 'on the watch' ]

1 . giving 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 to know about or understand something, especially a possible danger or problem:

The authorities should have been alert to the possibility of invasion.

—alertness noun [uncountable]

II. alert 2 BrE AmE verb [transitive]

1 . to officially warn someone about a problem or danger so that they are ready to deal with it:

The school immediately alerted the police.

2 . to make someone realize something important or dangerous

alert somebody to something

campaigns to alert the public to the dangers of HIV

• • •


▪ warn to tell someone about something bad or dangerous that might happen, so that they can avoid it or prevent it:

I warned you about sitting out in the sun too long.


We were warned that there could be delays on the motorway, so we took another route.

▪ give somebody a warning to tell someone that if they continue to behave in an unsatisfactory way, they will be punished:

He’s already been given several warnings about handing in his essays late.


The US gave a warning that if the hostages were not released, it would be forced to take military action.

▪ alert to officially or publicly warn people of possible danger so that they can prevent it or be ready to deal with it:

a campaign to alert people to the dangers of smoking


An anonymous caller alerted the police that a bomb was due to go off.

▪ tip somebody off informal to secretly warn someone about something that is going to happen – used especially about warning the police about a crime:

The police found the drugs after being tipped off by local residents.


Informants tipped the FBI off.

▪ caution formal to warn someone to do or not to do something in order to avoid a dangerous or bad result:

People are being cautioned against using credit cards abroad, in case of fraud.


Health officials have cautioned the public to wash fruit thoroughly before eating it.

▪ forewarn /fɔːˈwɔːn $ fɔːrˈwɔːrn/ [usually passive] formal to warn someone about something that is going to happen, so that you are expecting it or ready for it:

We had been forewarned that the roads weren’t very good.

III. alert 3 BrE AmE noun

1 . [countable] a warning to be ready for possible danger

a bomb/fire/terrorist etc alert

a full-scale flood alert

The bomb alert was raised soon after midnight.

⇨ ↑ red alert

2 . on (the) alert (for something/somebody) ready to notice and deal with a situation or problem:

Be on the alert for anyone acting suspiciously.

Troops in the vicinity were put on alert.

on full alert (also on high alert) (=completely ready to deal with a dangerous situation)

All our border points are on full alert.

• • •


▪ warning something that you say or do to tell people about danger, or to tell them not to do something:

All cigarette packets carry a government health warning.


She ignored her parents' warnings.


The army issued a warning that anyone who was out on the streets after dark was likely to be shot.

▪ caution formal an official warning or a piece of advice telling you to be careful:

Caution: do not install electrical equipment near or around water sources.


The video begins with a caution that you must do some warm-up exercises first.

▪ tip-off informal a warning that someone is about to do something, especially one given to the police about a crime:

Police were called to the hotel after a tip-off.

▪ alert a warning to be ready for possible danger that may happen soon:

Twelve flood alerts have been issued to areas along the River Severn.


a fire alert


The ambulance services were on red alert (=they were ready to take action immediately) .

▪ advisory formal an official warning or notice that gives information about a dangerous situation:

The air pollution gets so bad on some days that health advisories are posted at park entrances.

▪ caveat formal a warning that something may not be completely true, effective etc. Also used when pointing out that it is important to remember something:

The woman was offered treatment, but with the caveat that it had only a 30% chance of success.


One caveat is that you must take the goods back to the shop within 14 days.


There is one important caveat to this argument.

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.