red alert

noun

: the final stage of alert in which enemy attack appears imminent

broadly : a state of alert brought on by impending danger

Synonyms of red alert

• watch
• watchfulness
• alert
• alertness
• vigilance

Examples of red alert in a Sentence

The troops have been put on red alert.

the paparazzi were on red alert for sightings of the hot new Hollywood couple

Recent Examples on the Web

The national weather service expects to end its heat wave red alert warnings starting Wednesday, though thunderstorm warnings are now in place in several regions. — ABC News, 14 July 2026

Sunday’s stage through the Massif Central was won by Mathieu van der Poel, out-sprinting a small breakaway group, having been shortened by 30km due to a ‘red alert’ heatwave in the region. — Jacob Whitehead, New York Times, 13 July 2026

The center on Saturday also issued the first red alert for rainstorms of the year, according to state broadcaster CCTV. — Los Angeles Times, 11 July 2026

Three-quarters of France, encompassing tens of millions of people, was put under a red alert for extreme heat on Thursday and Friday as the mercury topped 40 C (104 F) in some locations, including in Paris. — Kirsten Grieshaber, Fortune, 27 June 2026

Word History

First Known Use

1941, in the meaning defined above