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
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.
During the 1890s and early 1900s, writers in Ireland found the way blocked by such parochial groups as the Vigilance Committee.
From The Wall Street Journal • Apr. 24, 2026
"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 and quick action are especially important here because Bifano only uses organic control methods, so no chemical pesticides or herbicides.
From Los Angeles Times • May 19, 2025
Vigilance committees formed across the entire South to ensure that nothing seditious was circulating.
From Salon • Mar. 19, 2025
William Still, a Negro, was the secretary of the Vigilance Committee.
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.