\ 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 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 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

Recent Examples on the Web: Noun

Police responded to reports of shots fired in the 500 block of Donna Drive, in a residential area off Turpin Street near the Glenn Highway, shortly after 4:30 p.m., according to an alert. Anchorage Daily News, "Shooting in East Anchorage sends 2 men to hospital, police say," 8 June 2019 Sky Harbor spokeswoman Krishna Patel said that Phoenix Fire and Airport Operations responded to the alert as a precaution. Melissa Yeager, azcentral, "Warning light leads Southwest pilot to declare emergency on arrival in Phoenix," 7 June 2019 The watch covers New Orleans as well as surrounding parishes, including Jefferson, St. Bernard, St. Tammany and the River Parishes, according to an alert issued by the National Weather Service Slidell office. Jennifer Larino,, "Tornado watch issued Thursday for New Orleans area," 6 June 2019 According to an alert posted at 10:43 p.m., shuttle buses will operate from Suffolk Downs to Government Center stations. Danny Mcdonald,, "Blue Line service suspended because of power problem," 7 July 2018 At least 25 people are dead and over 3,200 have been evacuated after Guatemala’s Fuego volcano erupted on Sunday, according to an alert from the National Coordinator for Disaster Reduction in Guatemala (CONRED). Lindsay Kimble,, "At Least 25 Dead After Volcano Erupts in Guatemala," 4 June 2018 According to the alert issued by the State Department on Wednesday, the cause of the injuries to the employee in China remains unknown. Michael Nedelman, CNN, "What we know about the possible 'sonic attacks' in Cuba and now China," 23 May 2018 Sacramento Police responded to a ShotSpotter alert shortly after midnight in the 3800 block of Dry Creek Road, a few blocks from Grant Union High School. Molly Sullivan, sacbee, "Shooting in Del Paso Heights leaves one dead, one injured | The Sacramento Bee," 22 May 2018 The assault and carjacking happened about 4 p.m., according to an alert sent out Sunday to UH students and employees. Alyson Ward, Houston Chronicle, "Student assaulted in carjacking on University of Houston campus," 20 May 2018

Recent Examples on the Web: Verb

In collaboration with the local health center, the scientists were alerted when someone tested positive for influenza. Debbie Ponchner, Scientific American, "New Finding Advances the Search for a Universal Flu Vaccine," 3 June 2019 Another user was alerted of a fire in her house by Furbo. Jessica Teich, Good Housekeeping, "The Furbo Dog Camera Is on Sale for $50 Off Right Now," 8 May 2019 Jayda’s sniffing alerted officers to the contraband. Natalie Dreier, ajc, "Police K-9 makes $10 million drug bust," 26 June 2018 But when the monitor alerted a probation officer that Maldonado had broken his curfew on March 30, 2016, the crime was already in progress. Marc Freeman,, "Life sentence for felon who wore GPS ankle monitor while raping West Boca woman," 19 June 2018 Related The Journal’s testing revealed that Facebook collects information from many popular smartphone apps, even if the user has no connection to Facebook, and often without any prominent or specific disclosure to alert the user. Georgia Wells, WSJ, "Cuomo Calls for Probe Into Facebook’s Collection of Sensitive Data from Apps," 22 Feb. 2019 Facebook, meanwhile, will begin to alert users who were impacted. Kurt Wagner, Recode, "Another Facebook bug may have exposed millions of users’ private photos to app developers," 14 Dec. 2018 Drivers usually call 911 or the Canadian Pacific Railway to alert and stop incoming trains while a stuck car is removed from the tracks. Karen Pilarski, Milwaukee Journal Sentinel, "Driver, toddler escaped from car stuck on railroad tracks in Wauwatosa minutes before train crash," 28 June 2018 The city is working to alert doctors and people in cocaine addiction, and health department staffers are handing out naloxone and information on the overdose cluster to drug users in West Philadelphia, Johnson said. Aubrey Whelan,, "Two people die in rash of crack-fentanyl overdoses in West Philadelphia," 26 June 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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Learn More about alert

Dictionary Entries near alert

Aleppo stone







Statistics for alert

Last Updated

28 May 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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