noun
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the fact, quality, or condition of being vigilant
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the abnormal state or condition of being unable to sleep
Usage
What does vigilance mean? Vigilance is the state of being watchful or alert for danger or some other kind of trouble. Vigilance is the noun form of the adjective vigilant, meaning watchful or alert. Vigilance 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. In a medical context, vigilance is sometimes used as a synonym for insomnia—the state of being unable to sleep. Example: We must be vigilant if we want to protect our home from invaders.
Other Word Forms
Derived Forms
Etymology
Origin of vigilance
First recorded in 1560–70; alteration ( -ance for -ancy) of obsolete vigilancy, from Latin vigilantia; see vigilant, -ancy
Explanation
Vigilance is devoted attentiveness or watchfulness. Security guards and test proctors alike need to practice vigilance. Vigilance comes from the Latin word for "wakefulness," vigilantia, and in a medical setting vigilance is still sometimes used to mean "insomnia." A prison guard might be required to maintain vigilance the whole time she's working, always being alert and watchful.
Vocabulary lists containing vigilance
"Harrison Bergeron"
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A Long Way Gone
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Fences
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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.
"There are also many things that need to be watched out for. Vigilance is key," says Min Thein Kyaw.
From Barron's • Dec. 21, 2025
Vigilance Elite recently took a minority stake in a new security app company, in exchange for advertising and marketing on his show.
From The Wall Street Journal • Oct. 12, 2025
Vigilance committees formed across the entire South to ensure that nothing seditious was circulating.
From Salon • Mar. 19, 2025
“Freedom is never really won – you earn it and win it in every generation. Vigilance is the answer,” she said.
From Seattle Times • Aug. 25, 2023
When the search for him had ended, the Boston Vigilance Committee sent him on to Canada via the Underground Railroad.
From "Harriet Tubman: Conductor on the Underground Railroad" by Ann Petry
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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.