vigilant
Americanadjective
-
keenly watchful to detect danger; wary.
a vigilant sentry.
- Antonyms:
- careless
-
ever awake and alert; sleeplessly watchful.
- Synonyms:
- sleepless, wide-awake
adjective
Usage
What does vigilant mean? To be vigilant is to be watchful or alert for danger or some other kind of trouble. Vigilant can describe a person or an action. It is often used when talking about keeping something out or in—whether that means keeping mistakes out of your work, robbers out of your home, or the dog inside the house. Example: We must be vigilant if we want to protect our home from invaders.
Synonym Usage
See alert.
Other Word Forms
Etymology
Origin of vigilant
First recorded in 1470–80; from Latin vigilant- (stem of vigilāns ), present participle of vigilāre “to be watchful”; see vigil, -ant
Compare meaning
How does vigilant compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
Use vigilant to describe someone who keeps awake and alert in order to avoid danger or problems. When taking the subway, be vigilant about your wallet — always know where it is, or someone might steal it from you. Vigilant descends from the Latin vigilare, "to be awake, watch," from vigil, "awake, alert." If you stay awake vigilantly all night, you're keeping watch or keeping a vigil. A vigilante (pronounced vij-uh-LAN-tee) is a person who acts outside the legal system to punish crime.
Vocabulary lists containing vigilant
100 Words Every Middle Schooler Should Know
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The Giver
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Hustled from the scene by a neighboring florist, she meets the vigilant but eccentric Neighborhood Watch group at the home of reclusive former detective Augusta Dupin.
From Los Angeles Times • May 12, 2026
The takeaway from your letter — and the lesson for readers — is that it’s important to be vigilant.
From MarketWatch • May 11, 2026
Koji Yamazaki, a leading bear expert and head of Ibaraki Nature Museum, said residents in the northern Tohoku region must stay vigilant this spring.
From Barron's • May 8, 2026
"As the threat level rises, I urge everyone to be vigilant, as they go about their daily lives, and report any concerns they have to the police," Mahmood added.
From BBC • Apr. 30, 2026
Always vigilant, Safari Hat took a couple steps toward us with an outstretched arm, her palm faceup and cupped.
From "The Miseducation of Cameron Post" by emily m. danforth
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
