2alert noun
plural alerts 1 [count] : something (such as a message or loud sound) that tells people there is some danger or problem : an alarm or signal of danger
▪ They sounded an alert when enemy planes were approaching the city. ▪ Medical officials have put out an alert to hospitals to look out for the virus. ▪ The government has issued a terrorism/security alert. 2 [noncount] : the state of being ready for something you have been warned about (such as an attack) — used with on ▪ We need to be on alert for any sudden changes. ▪ The attack could come at any time, so the soldiers need to be on full alert. ▪ The recently flooded community is again on high alert as more rain is expected. — see also red alert
▪ They sounded an alert when enemy planes were approaching the city. ▪ Medical officials have put out an alert to hospitals to look out for the virus. ▪ The government has issued a terrorism/security alert.
on the alert
: looking for or expecting something (such as danger or an opportunity)
▪ The soldiers need to be on the alert at all times. — often + for ▪ When you're driving in winter you should always be on the alert for icy conditions. ▪ I'm always on the alert for a good bargain.
▪ The soldiers need to be on the alert at all times. — often + for ▪ When you're driving in winter you should always be on the alert for icy conditions. ▪ I'm always on the alert for a good bargain.
