\ 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

Other Words from alert


alertly adverb
alertness noun

Synonyms & Antonyms for alert

Synonyms: Adjective

Synonyms: Noun

Synonyms: Verb

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

Adjective 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. Noun 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. Verb 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. See More
Recent Examples on the Web: Adjective The injured child was alert when taken to a hospital, police said. Rosana Hughes, ajc, 26 Apr. 2022 The woman, who was alert, was not believed to be the intended target. Christine Dempsey, Hartford Courant, 11 Apr. 2022 The victim was alert and taken to a hospital with non-life-threatening injuries. Fox News, 16 Feb. 2022 Drivers still need to be alert and paying attention to what’s up ahead. Eric D. Lawrence, Detroit Free Press, 21 Jan. 2022 Drivers need to be alert and prepared to take full control of their vehicle at any moment when using systems like Autopilot. Matt Mcfarland, CNN, 20 Jan. 2022 Walz said Glenn was alert afterward and the two spoke for about 10 minutes before emergency personnel took him to the hospital for observation. Mark Stewart, Milwaukee Journal Sentinel, 8 Jan. 2022 Hofford, who just took command of the fighter wing this month, is a native of Ashland, and often spends time at the beach with his family, and always is alert in case tsunami sirens go off after a big earthquake. oregonlive, 15 Dec. 2021 The boy soon started breathing again, and a few moments later was alert, reports. Cliff Pinckard, cleveland, 14 Dec. 2021 Recent Examples on the Web: Noun Baltimore Police were called to the 3000 Block of East Preston Street for a ShotSpotter alert just before 9:45 p.m. Mckenna Oxenden, Baltimore Sun, 10 May 2022 Police responded to 307 Zion St. at about 11:45 a.m. on a Shot Spotter alert and found the victim, in his 50s, suffering from a gunshot wound. Jesse Leavenworth, Hartford Courant, 10 May 2022 Stay informed on what’s happening across Michigan: Subscribe to our news alert emails. Gene Myers, Detroit Free Press, 9 May 2022 In its groundbreaking March 10 note, however, the Department of Labor saw this shift coming, and issued an alert that cheered the plaintiffs' bar, and greatly concerns employers. Shawn Tully, Fortune, 9 May 2022 The alert was issued Sunday upon the request of the University of Minnesota police. Danielle Wallace, Fox News, 9 May 2022 Given the possible link, though, this is the reason why the CDC has issued its specific health alert. Katia Hetter, CNN, 9 May 2022 Brightline has increased its efforts to curb deaths, including installing cameras to alert crews if someone is lurking near the tracks and adding fencing and landscaping to make access to the tracks more difficult. CBS News, 9 May 2022 The device could sound an audible alarm and send an alert to your phone, enabling you to take immediate action. cleveland, 8 May 2022 Recent Examples on the Web: Verb The brand is testing new cellular vehicle-to-everything (C-V2X) technology that will alert drivers that a school bus or ambulance is stopped on the road ahead. Sebastian Blanco, Car and Driver, 25 Apr. 2022 There are red flags that can alert you to a potential problem. Melissa Houston, Forbes, 13 Apr. 2022 But Hrytsenko’s company, Ajax Systems, had for years built apps that could alert a person’s smartphone even in sleep or silent mode. Washington Post, 16 Mar. 2022 Once a person is registered, the information is entered into a database that will alert emergency personnel when responding to a call with the individual or at their address. cleveland, 22 Jan. 2022 Also, many states have smartphone apps that can alert us to possible exposure, but that requires people to opt in. Mike Snider, USA TODAY, 20 Jan. 2022 There are many ways to scout for discounts, like following sites that alert you to sales. New York Times, 15 Dec. 2021 This break in the flow of light will alert the microcontroller, which will trigger a recording of the interruption as tampering. Manasee Wagh, Popular Mechanics, 11 Apr. 2022 Human scent can alert predators that young prey may be near. Karl Schneider, The Indianapolis Star, 21 Mar. 2022 See More

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.

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


borrowed from French alerte, going back to Middle French a l'herte "on guard, on the watch," borrowed from Italian all'erta, originally in the collocation stare all'erta "to be on the watch," literally, "to be on the height" (with erta "height, hill, steep ascent," noun derivative from feminine of erto, past participle of ergere "to raise, elevate," going back to Vulgar Latin *ērgere, by syncope from Latin ērigere) — more at erect entry 1

Note: The earliest citation for the word in the Oxford English Dictionary suggests direct borrowing from Italian, or at least recognition of an Italian source: "In this place the Prince [of Orange] finding his rutters [cavalry soldiers] alert, (as the Italians say) with aduise of his valiant brother, hee sent his Trumpets to D. d' Alua …." (Sir Roger Williams, The Actions of the Lowe Countries, London, 1618, p. 27).


noun derivative of alert entry 1 (or borrowed from French alerte, derivative of alerte, adjective)


verbal derivative of alert entry 1 or alert entry 2

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Last Updated

12 May 2022

Cite this Entry

“Alert.” Dictionary, Merriam-Webster, Accessed 23 May. 2022.

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More Definitions for alert


\ 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.

More from Merriam-Webster on alert

Nglish: Translation of alert for Spanish Speakers

Britannica English: Translation of alert for Arabic Speakers


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