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

All 27 cities Italy's health ministry monitors, including Rome, Naples, Venice, and Bologna, are on red alert this week. — Scott Simon, NPR, 8 Aug. 2026

To top it off, the region has seen several heatwaves over the summer that have prompted red alerts, threat-to-life warnings, and droughts, as temperatures have regularly exceeded 104 degrees Fahrenheit. — Sawdah Bhaimiya, CNBC, 7 Aug. 2026

Italy’s Health Ministry placed all 27 cities monitored under its national heat surveillance system on red alert Thursday — the first time this year the entire network has been under the highest warning level simultaneously. — ABC News, 6 Aug. 2026

Deaths in Greece In Italy, 25 cities were put under a red alert on Monday as the fourth heat wave of the year hits, according to the country’s Health Ministry. — Billy Stockwell, CNN Money, 3 Aug. 2026

Word History

First Known Use

1941, in the meaning defined above