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English definition of “alarm”

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alarm

noun uk   /əˈlɑːm/ us    /-lɑːrm/

alarm noun (WARNING)

[C] a warning of danger, usually a loud noise or flashing light: If there's any trouble, raise/sound the alarm by pulling the emergency cord. The first two bomb alerts were false alarms, but the third was for real.B1 [C] a device that makes a loud noise to warn of danger: a burglar/car/fire/smoke alarmA2 [C] an alarm clock B1 [C] If an electronic device such as a watch or computer has an alarm, it can be set to make a noise at a particular time.
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alarm noun (WORRY)

C2 [U] sudden worry and fear, especially that something dangerous or unpleasant might happen: I didn't tell her that he was late because I didn't want to cause her any alarm. Villagers have reacted with alarm to news of a proposed new road.
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alarm

verb [T] uk   /əˈlɑːm/ us    /-lɑːrm/
C1 to make someone worried or frightened: I didn't want to alarm him by telling him that she was ill.
(Definition of alarm from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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