Meaning & use
alert
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Meanings
adjectivecomparable
Wide awake, watchful, and quick to notice and respond to what is happening.
Grammar: Can follow a linking verb or come before a noun: she stayed alert; an alert driver.
Patterns
- alert to something
- stay alert
- remain alert
The guard stayed alert all night.
An alert nurse noticed the change in his breathing.
Drivers must remain alert on long journeys.
nouncountable
A signal or message that warns people of danger or tells them something needs attention.
Grammar: Countable: a weather alert, several alerts.
Patterns
- issue an alert
- an alert about something
- on alert
The city issued a flood alert on Tuesday.
My phone sent an alert when the package arrived.
The hospital is on alert after the outbreak.
verbtransitive
To warn someone about a danger or problem so that they can act quickly.
Grammar: Takes an object, often with to: alert the police; alert them to the risk.
Patterns
- alert someone to something
- alert someone that
A loud alarm alerted residents to the fire.
She alerted her manager that the system was down.
Neighbors alerted the police when they heard breaking glass.
Word forms
| comparative | more alert |
|---|---|
| superlative | most alert |
| plural | alerts |
| third person singular | alerts |
| past tense | alerted |
| -ing form | alerting |
Common combinations
- stay alert
- Try to stay alert during the night shift.
- on high alert
- Police were on high alert during the festival.
- alert to danger
- Hikers should be alert to danger on the trail.
- issue an alert
- Officials issued an alert about the storm.
- alert the authorities
- The staff alerted the authorities at once.
- wide awake and alert
- After the coffee, he felt wide awake and alert.
Synonyms and how they differ
- vigilant
- Vigilant is more formal and suggests careful watching for a specific danger over a long period, while alert is more general.
- attentive
- Attentive means paying close attention to what someone says or needs, not necessarily watching for danger.
- warn
- Warn is the usual verb for telling someone of a danger, while alert sounds more urgent and often means a quick notification.
- watchful
- Watchful suggests keeping an eye on something, whereas alert includes being ready to react quickly.
Opposites
Word family
- alertly adverb
- in a watchful, ready way
- alertness noun
- the state of being watchful and ready
- alerting noun
- the act of warning people
Commonly confused: alert or alter?
alert vs alter
Alter means to change something, and is spelled and sounded similarly to alert but has no meaning of warning.
Practice
The lifeguard's quick reaction was due to staying ______ to any sign of trouble in the water.
Choose one answer.
Alert to means watchful for, which fits the lifeguard. Alter and altered are different words meaning change, and alerting does not complete the phrase staying ___ to.
Make it your own
Write a sentence using “alert”, then check it and compare it with the examples above.