alarm

/əˈlɑːm/noun

A sound or signal that warns people of danger or calls for their attention.

Example sentence

“The fire alarm went off in the middle of the night.”

"Raise the alarm" means to warn others of danger; "false alarm" means the danger never existed.

Related words

uneaseA feeling of worry or discomfort; a sense that something is wrong.horrorA powerful feeling of shock, fear, or disgust.apprehensionA feeling of worry or dread about something bad that might happen.frightA sudden, sharp burst of fear brought on by the unexpected appearance of danger, usually passing quickly.distressStrong pain, worry, or suffering of the body or mind, often sudden and severe.terrorA feeling of extreme fear.