follow Dictionary.com

Your favorite word could be our Word of the Day!

alert

[uh-lurt] /əˈlɜrt/
adjective
1.
fully aware and attentive; wide-awake; keen:
an alert mind.
2.
swift; agile; nimble.
noun
3.
an attitude of vigilance, readiness, or caution, as before an expected attack.
4.
a warning or alarm of an impending military attack, a storm, etc.:
We'd just boarded the bus when the alert sounded.
5.
the period during which such a warning or alarm is in effect.
verb (used with object)
6.
to warn (troops, ships, etc.) to prepare for action.
7.
to warn of an impending raid, attack, storm, etc.:
The radio alerted coastal residents to prepare for the hurricane.
8.
to advise or warn; cause to be on guard:
to alert gardeners to the dangers of some pesticides.
Idioms
9.
on the alert, on guard against danger; in readiness; vigilant:
The state police are on the alert for an escaped convict believed to be in the area.
Origin
1590-1600
1590-1600; 1940-45 for def 4; < Italian all'erta, equivalent to all(a) to, on the + erta lookout, watchtower, orig. feminine of erto, past participle of ergere < Latin ērigere to erect
Related forms
alertly, adverb
alertness, noun
hyperalert, adjective
unalerted, adjective
Synonyms
1. awake, wary, observant. Alert, vigilant, watchful imply a wide-awake attitude, as of someone keenly aware of his or her surroundings. Alert describes a ready and prompt attentiveness together with a quick intelligence: The tourist was alert and eager to see the sights. Vigilant suggests some immediate necessity for keen, active observation, and for continuing alertness: Knowing the danger, the scout was unceasingly vigilant. Watchful suggests carefulness and preparedness: watchful waiting. 2. brisk, lively, quick, active, sprightly, spirited.
Antonyms
1. unaware.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source
Examples from the web for alertness
  • All over town, tiny green lizards hold their heads up with notable alertness.
  • That's because, by cooling the brain, yawning enhances alertness and overall mental efficiency.
  • Many indigenous communities live in a permanent state of defensive alertness.
  • It is my favorite shot in the series because of the snake's alertness as it searches the air with its tongue for scents.
  • Equally imperative was alertness to the era's political movements.
  • But the impressive thing was his fellow student's alertness, which stemmed from affection.
  • Within a decade, some say, continuous alertness could be available over the counter.
  • Changing positions helps increase circulation and improve alertness.
  • She had been touched with a point that made her quiver, and she needed all the alertness of her will to repress her agitation.
  • Our body regulates everything from temperature to alertness with feedback loops.
British Dictionary definitions for alertness

alert

/əˈlɜːt/
adjective (usually postpositive)
1.
vigilantly attentive: alert to the problems
2.
brisk, nimble, or lively
noun
3.
an alarm or warning, esp a siren warning of an air raid
4.
the period during which such a warning remains in effect
5.
on the alert
  1. on guard against danger, attack, etc
  2. watchful; ready: on the alert for any errors
verb (transitive)
6.
to warn or signal (troops, police, etc) to prepare for action
7.
to warn of danger, an attack, etc
Derived Forms
alertly, adverb
alertness, noun
Word Origin
C17: from Italian all'erta on the watch, from erta lookout post, from ergere to build up, from Latin ērigere; see erect
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for alertness
n.

1714, from alert + -ness.

alert

adv.

"on the watch," 1590s, from French alerte "vigilant" (17c.), from phrase à l'erte "on the watch," from Italian all'erta "to the height," from erta "lookout, high tower," noun use of fem. of erto, past participle of ergere "raise up," from Latin erigere "raise" (see erect). The adjective is attested from 1610s, the noun from 1803, and the verb from 1868. Related: Alerted; alerting.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
Related Abbreviations for alertness

ALERT

Allergy to Latex Education and Resource Team
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Idioms and Phrases with alertness

alert

The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source

Word of the Day

Difficulty index for alert

Most English speakers likely know this word

Word Value for alertness

9
11
Scrabble Words With Friends

Quotes with alertness

Nearby words for alertness