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.

---

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

---

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.

---

Etymology

Origin of false alarm

First recorded in 1570–80

Example Sentences

Doubts about the current bull market have started to creep in following Friday’s tech stock wipeout, but this wouldn’t be the first false alarm.

From The Wall Street Journal • Jun. 8, 2026

This misinterpretation activates the cell's innate immune system, creating a false alarm that can lead to inflammation and disease.

From Science Daily • Feb. 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

That turned out to be a false alarm, with a mechanic finding only a malfunction with a warning light.

From Los Angeles Times • Oct. 31, 2025

I think the fire marshal was just mad about our false alarm, and I think Terupt knew that, too.

From "Because of Mr. Terupt" by Rob Buyea