sound the alarm Definition

alarm
noun

1. Sudden fear produced by awareness of danger.

Thesaurus: fear, dread, fright, trepidation.
2. A noise warning of danger.

Thesaurus: siren, bell, signal, shout, yell, scream.
3. A bell, etc which sounds to warn of danger or, eg on a clock, to wake a person from sleep.
4. An alarm clock.

verb alarmed, alarming

1. To frighten.

Thesaurus: frighten, scare, panic, startle, distress, dismay, daunt.
2. To warn someone of danger.
3. To fit or switch on an alarm on (a house, car, etc).

Idiom: give the alarm (raise the alarm, sound the alarm)

To give warning of danger by shouting, ringing a bell, etc.

Etymology: 14c: from French alarme, from Italian all'arme to arms.