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English definition of “alert”

alert

verb [T]     /əˈlɜːt/ US  /-ˈlɝːt/
C2 to warn someone of a possibly dangerous situation: An anonymous letter alerted police to the possibility of a terrorist attack at the airport.Threats and warnings
(Definition of alert verb from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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