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

The ShakeAlert system that warns about imminent shaking arriving from earthquakes sent a false alarm across California on Thursday morning for a magnitude 5.9 temblor that did not happen.

From Los Angeles Times

“After an extensive investigation, the incident was determined to be a false alarm,” the statement said.

From Los Angeles Times

Others, the sweet relief of a false alarm and disaster narrowly averted.

From Los Angeles Times

The ShakeAlert computer system that warns about the imminent arrival of shaking from earthquakes sent out a false alarm Thursday morning for a magnitude 5.9 temblor in Carson City, Nev., that did not actually happen.

From Los Angeles Times

The window had been disconnected from the alarm system after a defect caused repeated false alarms.

From The Wall Street Journal