\ ə-ˈlərt How to pronounce alert (audio) \

Definition of alert

 (Entry 1 of 3)

1a : watchful and prompt to meet danger or emergency an alert guard trying to stay alert to possible problems
b : quick to perceive and act mentally alert
2 : active, brisk elicited an alert response



Definition of alert (Entry 2 of 3)

1 : a state of careful watching and readiness especially for danger or opportunity on 24-hour alert
2a : an alarm or other signal of danger traffic alerts They sounded the alert.
b : an urgent notice … an alert to parents … about new immunization requirements.— Ann Schrader
3 : the period during which an alert is in effect
on the alert
: looking for or expecting something (such as danger or an opportunity) Drivers need to be on the alert for icy condition. always on the alert for a good bargain


alerted; alerting; alerts

Definition of alert (Entry 3 of 3)

transitive verb

1 : to call (someone) to a state of readiness : warn alerted the school board of a possible teachers' strike alert the authorities
2 : to make (someone) aware of something alerted the public to the dangers of pesticides

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Other Words from alert


alertly adverb
alertness noun

Synonyms & Antonyms for alert

Synonyms: Adjective

Argus-eyed, attentive, awake, observant, open-eyed, tenty (also tentie) [Scottish], vigilant, watchful, wide-awake

Synonyms: Noun

admonishment, admonition, alarm (also alarum), caution, forewarning, heads-up, notice, warning

Synonyms: Verb

advise, caution, forewarn, wake, warn

Antonyms: Adjective


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Choose the Right Synonym for alert


watchful, vigilant, wide-awake, alert mean being on the lookout especially for danger or opportunity. watchful is the least explicit term. the watchful eye of the department supervisor vigilant suggests intense, unremitting, wary watchfulness. eternally vigilant in the safeguarding of democracy wide-awake applies to watchfulness for opportunities and developments more often than dangers. wide-awake companies latched onto the new technology alert stresses readiness or promptness in meeting danger or in seizing opportunity. alert traders anticipated the stock market's slide

intelligent, clever, alert, quick-witted mean mentally keen or quick. intelligent stresses success in coping with new situations and solving problems. an intelligent person could assemble it fast clever implies native ability or aptness and sometimes suggests a lack of more substantial qualities. clever with words alert stresses quickness in perceiving and understanding. alert to new technology quick-witted implies promptness in finding answers in debate or in devising expedients in moments of danger or challenge. no match for his quick-witted opponent

Examples of alert in a Sentence


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


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 alert.


Several neighbors alerted the authorities when they noticed strangers acting suspiciously. The governor alerted island residents that a hurricane was coming. The teacher alerted the students that tests would be given the next day.
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Recent Examples on the Web: Adjective

Written in consultation with haredi copywriters, the leaflets urge Jewish guests to be alert to lines and leave campgrounds clean. Cnaan Liphshiz,, "In the Swiss Alps, locals and haredi Orthodox tourists find ways to get along," 2 July 2019 No other teams have played each other on more occasions at Women’s World Cups so Sweden should have been alert to the danger the defending champions pose at set pieces. Dylan Bouscher, The Mercury News, "Photos: Team USA comfortably beats Sweden in Women’s World Cup, sets another record," 20 June 2019 Working in a profession known to be dangerous, he was trained to be alert to threats posed to deputy sheriffs like him. Maya Lau,, "After confronting a threat, Deputy Joseph Solano remembered for his courage and kindness," 14 June 2019 The officer, who was not identified, was conscious and alert after the shooting, Jachles said. Michael Williams,, "Corrections officer wounded at Orange County Sheriff’s Office gun range, firefighters say," 7 June 2019 The result was a match largely devoid of interesting moments, though Frei had to be alert throughout. Geoff Baker, The Seattle Times, "Sounders survive last-minute scare to extend unbeaten mark to four games," 31 Mar. 2019 Minnesota travelers, be alert — health officials have a message for you: be on the lookout for measles symptoms. Zoe Szathmary, Fox News, "Minnesota health department reports 'third travel-related case of measles' in less than 6 weeks," 18 Sep. 2018 The newest watch can detect hard falls and alert emergency contacts. Dan Gallagher, WSJ, "It Is Prime Time for Smartwatches," 6 Mar. 2019 In surveillance video, Martinez appeared to alert customers to her attacker. Katherine Lam, Fox News, "Jogger stabbed to death in Washington, DC, collapses in takeout restaurant as attacker flees, cops say," 19 Sep. 2018

Recent Examples on the Web: Noun

The immediate benefit of the Rapid Alert System is not actually the alerts, said Mr. Güllner, the senior counter-disinformation official. Matt Apuzzo, New York Times, "Europe Built a System to Fight Russian Meddling. It’s Struggling.," 6 July 2019 Residents can also sign up to get emergency alerts by cell phone during a disaster. Ramona Sentinel, "Strong quake prompts preparedness reminders from county," 5 July 2019 Currently, most of the groups that get alerts are industries, hospitals, and emergency and transit systems — not the general public. Mary Beth Griggs, The Verge, "LA’s earthquake warning system worked — just not how people expected," 5 July 2019 Right now, Los Angeles is the only place in California where the public can get alerts. Paul Rogers, The Mercury News, "When will the Bay Area get an earthquake warning system?," 5 July 2019 Fire officials have issued Level 2 alerts -- be ready to evacuate if necessary -- for residents of 180 structures in the Lincoln Creek, McCloud and Vancouver subdivisions. Zaz Hollander, Anchorage Daily News, "Hundreds of Fairbanks-area residents under precautionary wildfire evacuation alerts," 5 July 2019 That news has put the Premier League trio on alert, particularly after 22-year-old played a starring role Spain's Under-21 European Championship-winning side last month., "Liverpool Join Tottenham & Arsenal in Race for Real Madrid Star Dani Ceballos," 4 July 2019 There were no news alerts, no way for photos to go viral, no mechanism for a kid on the Gulf Coast to hear these unlikely heroes tell their stories. CBS News, "Tim Cook on the work still needed for LGBTQ equality," 30 June 2019 The danger, though, lies in over-hyping the lasting significance of this (cliché alert) viral moment more than seven months before the Iowa caucuses. Walter Shapiro, The New Republic, "Joe Biden: Bruised Over Busing, But Still Standing," 28 June 2019

Recent Examples on the Web: Verb

But that's when VAR intervened and alerted the referee the possibility of a foul. Luis Miguel Echegaray,, "VAR Gives USA Penalty in Women’s World Cup Final vs. Netherlands," 7 July 2019 Our threshold at the moment is to maximize public safety and minimize over-alerting. Mary Beth Griggs, The Verge, "LA’s earthquake warning system worked — just not how people expected," 5 July 2019 The child was taken to a hospital in a private vehicle, and a security guard there alerted police, Finner said. Julian Gill, Houston Chronicle, "2-year-old girl 'fighting for her life' after being shot in the head in north Houston," 5 July 2019 The discovery in Worcester, about 40 miles from Boston, was reported early Wednesday when the engineer of a slow-moving train alerted the conductor to the babies, and the locomotive was stopped. Dennis Romero, NBC News, "Twin infants found near railroad tracks in Massachusetts," 5 July 2019 Monitor the news: The government will likely alert the public with emergency instructions via TV, social media and radio, so look to your devices for updates. Scottie Andrew And Katherine Dillinger, CNN, "Here's how to stay safe before, during and after an earthquake strikes," 4 July 2019 In that incident, according to the incident summary, three male suspects cut the screen out of a rear basement window and at least one entered the home when the family dogs alerted the homeowners to their presence and the suspects fled. Libby Solomon,, "Towson-area crime: Homeowner punches man trying to climb through his bedroom window," 3 July 2019 Sheriff’s officials said that shortly after 8 p.m., inmates noticed Smith exhibiting signs of a seizure and alerted jail officers. Carol Robinson |,, "Jefferson County jail inmate dies after plastic bag ruptures in stomach," 2 July 2019 Someone better alert all of the group chats that this season sounds unmissable. Allie Gemmill, Teen Vogue, ""Stranger Things" Cast Kicked Joe Keery Out of the Group Chat for Being "Too Old"," 2 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'alert.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of alert


1618, in the meaning defined at sense 1a


1801, in the meaning defined at sense 1


circa 1868, in the meaning defined at sense 1

History and Etymology for alert

Adjective, Noun, and Verb

Italian all'erta, on the watch, literally, on the height

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Dictionary Entries near alert

Aleppo stone







Statistics for alert

Last Updated

9 Jul 2019

Look-up Popularity

Time Traveler for alert

The first known use of alert was in 1618

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More Definitions for alert



English Language Learners Definition of alert

 (Entry 1 of 3)

: able to think clearly and to notice things



English Language Learners Definition of alert (Entry 2 of 3)

: 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)



English Language Learners Definition of alert (Entry 3 of 3)

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


\ ə-ˈlərt How to pronounce alert (audio) \

Kids Definition of alert

 (Entry 1 of 3)

1 : watchful and ready especially to meet danger But he was alert at night, too, on the road, always listening intently …— Lois Lowry, The Giver
2 : quick to understand and act An alert reader noticed the error in grammar.

Other Words from alert

alertly adverb The prairie dog sat alertly beside the opening of its burrow.



Kids Definition of alert (Entry 2 of 3)

1 : an alarm or signal of danger The police issued an alert.
2 : the period during which an alert is in effect We stayed indoors during the alert.
on the alert
: watchful against danger … the remark had set us all on the alert, straining ears and eyes …— Robert Louis Stevenson, Treasure Island


alerted; alerting

Kids Definition of alert (Entry 3 of 3)

: to make aware of a need to get ready or take action : warn The siren alerted us that a tornado was approaching.

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More from Merriam-Webster on alert

Rhyming Dictionary: Words that rhyme with alert

Thesaurus: All synonyms and antonyms for alert

Spanish Central: Translation of alert

Nglish: Translation of alert for Spanish Speakers

Britannica English: Translation of alert for Arabic Speakers

Comments on alert

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an act or instance of editing or removing

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