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
Derived 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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List 3
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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.
She sets screens that get scrutinized as if by the most vigilant TSA agent.
From Los Angeles Times • Jun. 12, 2026
So we need to make sure that we’re holding these people accountable and stay eternally vigilant with everything that’s happening.
From Salon • Jun. 12, 2026
“We just need to remain absolutely vigilant, cautious and diligent,” said Macy Steers, co-head of financial lines at CNA Insurance.
From The Wall Street Journal • Jun. 2, 2026
Seventeen departments of France - in the north-west, as well as Paris - are under an orange alert, indicating people should be "very vigilant" about the weather.
From BBC • May 28, 2026
By that point, nearly every effort to send a US agent behind the Iron Curtain had failed; the KGB was simply too well entrenched and too vigilant for the Americans to sneak past its nets.
From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau
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.
