alert
Able to see and understand things quickly, and act on them.
Quick to notice and react to possible danger, problems, or changes.
A message or sound that tells you there is danger or something important.
A warning or signal that something dangerous or important is happening or might happen.
To let someone know there is danger or something important happening.
To tell someone about a dangerous or important situation so they can prepare or act.
- Base: alert
- Base: alert
- Plural: alerts
- Base: alert
- 3rd Person Singular: alerts
- Present Participle: alerting
- Past: alerted
alert someone to something
1Inform someone about specific danger/problem
To tell a person about a particular danger or problem so they can act.
- She alerted me to the broken step.
- The app alerts users to new updates.
keep someone alert
3Make someone stay aware and ready
To make a person stay aware and ready to act quickly.
- The coach’s questions kept the players alert.
- Good lighting keeps drivers alert at night.
on high alert
2In maximum readiness for danger
In a state of being ready to act quickly because something bad may happen.
- The city is on high alert after the attack.
- Soldiers are on high alert along the border.
red alert
4Highest level of warning
The most serious warning that something dangerous is happening or will happen soon.
- The military went on red alert during the crisis.
- We are on red alert for possible flooding.