on alert

ADJECTIVE

on call

Synonyms

WEAK

accessible at hand at one's beck and call at one's disposal at one's fingertip available handy night call on deck on-the-spot prepared standing by within reach

ADJECTIVE

vigilant

Synonyms

STRONGEST

anxious attentive aware cautious circumspect keen observant wary

WEAK

acute agog alert guarded looking for looking to on guard on the ball on the job on the lookout on the qui vive on toes open-eyed sharp sleepless unsleeping waiting on wakeful wide-awake with eyes peeled with weather eye open

Antonyms

STRONGEST

careless heedless ignorant inattentive incautious indifferent indiscreet rash thoughtless unaware uncareful unobservant

WEAK

impulsive negligent

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

But for now, players and medical staff are on alert.

From Los Angeles Times • Jun. 14, 2026

The Soviet foreign minister, Andrei Gromyko, observed at the time: “Americans put forces on alert so often that it is hard to know what it means.”

From Slate • Apr. 21, 2026

On Sunday morning internal health service communications went out across Kent and Medway informing services of the outbreak, so NHS 111, local A&Es and GPs were on alert for cases.

From BBC • Mar. 24, 2026

Global defense spending reached $2.63 trillion in 2025, according to the International Institute for Strategic Studies, with the world on alert as conflicts in Ukraine and Iran intensify.

From The Wall Street Journal • Mar. 11, 2026

They put the Nazis on alert, despite their fear of their government and the strong-armed reach of the Gestapo and SS.

From "Hitler Youth: Growing Up in Hitler's Shadow" by Susan Campbell Bartoletti

on alert

Example Sentences

Related Words