false alarm

American  

noun

1. a false report of a fire in progress to a fire department.

2. something that excites unfounded alarm or expectation.

   Rumors of an impending transit strike proved to be a false alarm.

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false alarm British  

noun

1. a needless alarm given in error or with intent to deceive

2. an occasion on which danger is perceived but fails to materialize

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false alarm Idioms  

1. A warning signal that is groundless, made either by mistake or as a deliberate deception. For example, The rumor that we were all going to get fired was just a false alarm, or Setting off a false alarm is a criminal offense. This expression, first recorded in 1579, today is often used for a report of a nonexistent fire.

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Etymology

Origin of false alarm

First recorded in 1570–80

Example Sentences

Chronic pain, however, continues even after the injury has healed, creating a kind of false alarm that can last for weeks, months, or years.

From Science Daily • Apr. 27, 2026

Reul said they saw "no smoke, no smell of fire, or damage", so they "concluded it was a false alarm", which he said was not unusual.

From BBC • Feb. 14, 2026

I see some information about cops scrambling, but an editor says it’s a false alarm and not to worry about it.

From Slate • Jun. 17, 2025

Weiss is about to get his first face-to-face with Spears, but it’s a false alarm: She thinks Weiss is a production assistant.

From Los Angeles Times • Jun. 9, 2025

Unsurprisingly, Mr. Weasley found, upon arrival at Mr. Moody’s heavily guarded house, that Mr. Moody had once again raised a false alarm.

From "Harry Potter And The Goblet Of Fire" by J. K. Rowling