Meaning of ALERT in English

ALERT

/ əˈlɜːt; NAmE əˈlɜːrt/ adjective , verb , noun

■ adjective

1.

able to think quickly; quick to notice things :

Suddenly he found himself awake and fully alert.

Two alert scientists spotted the mistake.

2.

alert to sth aware of sth, especially a problem or danger :

We must be alert to the possibility of danger.

►  alert·ly adjective

►  alert·ness noun [ U ]

■ verb [ often passive ]

1.

to warn sb about a dangerous or urgent situation :

[ vn ]

Neighbours quickly alerted the emergency services.

Alerted by a noise downstairs, he sat up and turned on the light.

[also vn ( that ), vn to inf ]

2.

[ vn ] ~ sb to sth to make sb aware of sth :

They had been alerted to the possibility of further price rises.

■ noun

1.

[ sing. , U ] a situation in which people are watching for danger and ready to deal with it :

Police are warning the public to be on the alert for suspicious packages.

More than 5 000 troops have been placed on (full) alert .

2.

[ C ] a warning of danger or of a problem :

a bomb / fire alert

—see also red alert

••

WORD ORIGIN

late 16th cent. (originally in military use): from French alerte , from Italian all' erta to the watchtower.

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.