adjective \ə-ˈlərt\

: able to think clearly and to notice things

Full Definition of ALERT

a :  watchful and prompt to meet danger or emergency
b :  quick to perceive and act
:  active, brisk
alert·ly adverb
alert·ness noun

Examples of ALERT

  1. An alert guard stopped the robbers.
  2. He was tired and had trouble staying alert while he was driving.
  3. She wasn't mentally alert enough to answer the questions.
  4. An alert watchdog guarded the door.

Origin of ALERT

Italian all'erta, on the watch, literally, on the height
First Known Use: 1618



: something (such as a message or loud sound) that tells people there is some danger or problem : an alarm or signal of danger

: the state of being ready for something you have been warned about (such as an attack)

Full Definition of ALERT

:  a state of careful watching and readiness especially for danger or opportunity <on 24-hour alert>
a :  an alarm or other signal of danger
b :  an urgent notice <an alert to parents … about new immunization requirements — Ann Schrader>
:  the period during which an alert is in effect

Examples of ALERT

  1. They sounded an alert when enemy planes were approaching the city.
  2. Medical officials have put out an alert to hospitals to look out for the virus.
  3. The government has issued a terrorism alert.

First Known Use of ALERT




: to give (someone) important information about a possible problem, danger, etc. : to warn (someone)

: to make (someone) aware of something

Full Definition of ALERT

transitive verb
:  to call to a state of readiness :  warn
:  to make aware of <alerted the public to the dangers of pesticides>

Examples of ALERT

  1. Several neighbors alerted the authorities when they noticed strangers acting suspiciously.
  2. The governor alerted island residents that a hurricane was coming.
  3. The teacher alerted the students that tests would be given the next day.

First Known Use of ALERT

circa 1868


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May 25, 2015
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