\ 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

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 Croatia had opportunities to extend their lead with good chances inside the box, however alert goalkeeping from Schmeichel kept the scores down and helped the game to develop some sort of rhythm after a crazy opening., "Croatia 1-1 Denmark (3-2 Pens): Ivan Rakitić Breaks Danish Hearts Despite Kasper Schmeichel Heroics," 2 July 2018 The Florida Department of Law Enforcement put out the alert Saturday morning. Monique O. Madan, miamiherald, "These three children have gone missing together. Police need your help.," 30 June 2018 According to Everyday Health, meditation can improve concentration, reduce stress, prevent cognitive decline, and keep your brain healthy and alert as you age. Jessica Leigh Mattern, Woman's Day, "30 Fun Things to Do By Yourself in Your Lifetime," 3 Jan. 2019 The students also reported feeling less sleepy and more alert. Angela Chen, The Verge, "Why we might want the school day to start later," 12 Dec. 2018 The result is military personnel more alert, focused, and better able to do their jobs. Kyle Mizokami, Popular Mechanics, "A New Electronic Device Could Cure the Military's Big Motion Sickness Problem," 22 Nov. 2018 Hence, if software can drive as well as the average sober, alert human driver, its widespread use would save thousands of lives per year. Timothy B. Lee, Ars Technica, "Car crashes killed 37,133 people in the US in 2017," 3 Oct. 2018

Recent Examples on the Web: Noun

The alert said the group was targeting churches and had already scouted locations. Niharika Mandhana, WSJ, "Sri Lanka Bombings Put Focus on Islamist Preacher Long on the Radar," 26 Apr. 2019 The first fire alarm at Notre-Dame was triggered on Monday, April 15 at 6:20 p.m. The cathedral was evacuated and the alert was investigated but there was no sign of fire found on the scene, a spokesman for the Paris fire brigade told CNN. Lauren Hubbard, Town & Country, "What Caused the Massive Fire at Notre-Dame Cathedral?," 16 Apr. 2019 To sign up for alerts for any of these brands, visit and download the Wayfair app. Shanon Maglente, Good Housekeeping, "Wayfair's Way Day Sale is Happening NOW — Here's Everything You Need to Know," 10 Apr. 2019 We’re taught from our hormone-riddled teen years to be on high alert for acne—and to attack it with every product under the sun at the first sign of a zit. Sara Coughlin, SELF, "How to Know if You Have 'Fungal Acne'—and How to Treat it," 1 Apr. 2019 Vogueworld Jessie J and Channing Tatum Mark Their New Romance With a Subtle Fashion Statement New couple alert! Vogue, "Jessie J and Channing Tatum Mark Their New Romance With a Subtle Fashion Statement," 14 Mar. 2019 From May to October, much of California—plus parts of most states west of the Rockies—would be on alert for dry conditions. Kevin Dupzyk, Popular Mechanics, "The Tank That's Tougher Than Wildfire," 13 Nov. 2018 There have been seven days of alerts for the Baton Rouge area. Sara Sneath,, "New Orleans seeing an increase in air quality alerts: Here's why," 11 May 2018 One partner had a physical or emotional affair Texting daily with a coworker, chatting up that cute barista, or getting alerts for every post your ex makes on social media may seem like harmless behaviors. Madeleine Burry,, "6 Signs It's Time to Go to Couples Therapy," 11 May 2018

Recent Examples on the Web: Verb

Onboard systems collect data on submarines, fishing boats and pollution, firing off alerts via satellite to authorities. The Economist, "Avast, me hearties," 5 July 2018 The Google alerts lit her cell as her name flamed up on Twitter. Bryan Smith, Los Angeles Magazine, "How Lisa Bloom Bounced Back From Defending Harvey Weinstein," 8 June 2018 Paz de la Huerta awoke Friday morning in France to a text message from a friend, alerting her that Harvey Weinstein was about to be arrested in New York and charged with rape. Rebecca Keegan, HWD, "Paz de la Huerta on Harvey Weinstein’s Arrest: “I Couldn’t Stop Crying. I Don’t Know Why.”," 25 May 2018 This alerts the port-hogger immediately to their faux pas. Jessica Pan, The Cut, "The 10 Most Bizarre Royal Etiquette Rules," 17 May 2018 There is no flag option in its request form to alert them of a request’s scope or time-sensitivity. Rossalyn Warren, The Atlantic, "Should the Internet Forget Italy's Most Viral Sex Tape?," 16 May 2018 Now the last driver to pull in can alert the world that the lot is full. David Pogue, Scientific American, "These Apps Don't Exist Yet--but They Should," 15 May 2018 The mystery of what happened to the Harts, the possible warning signs that alerted some of their neighbors, and the ongoing investigation by law enforcement are documented in the Glamour podcast Broken Harts. Lauren Smiley, Glamour, "Sarah Hart Was ‘Intoxicated’: Everything We’ve Learned So Far About the Hart Family From the Coroner’s Inquest," 5 Apr. 2019 The shaking often alerts people and warning systems to be on the lookout for the movement of water towards or away from the coast. Mary Beth Griggs, The Verge, "Deadly Indonesian tsunami was not caused by an earthquake," 23 Dec. 2018

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

2 Apr 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

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