noun
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the tendency to be untruthful
-
a falsehood
Other Word Forms
Etymology
Origin of mendacity
1640–50; < Late Latin mendācitās falsehood, equivalent to Latin mendāci- (stem of mendāx ) given to lying, false + -tās -ty 2
Explanation
Mendacity is a tendency to lie. Your friend might swear that he didn't eat your secret chocolate stash, but you'll find it hard to believe him if he's known for his mendacity. Anyone in the habit of lying frequently has the characteristic of mendacity. People often accuse government officials of mendacity, or being less than honest. You're bound to get frustrated by the mendacity of your friend who's a pathological liar. Mendacity comes from the Latin root word mendacium, or "lie." Don't confuse mendacity with a similar-sounding word, audacity — which means "fearlessness, daring, or bravery."
Vocabulary lists containing mendacity
A Web of Lies
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Pygmalion
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Word Warriors: Four Years of Words Worth Reviving
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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.
A few chapters occupy his immediate point of view, but the novel never tries to explain his mendacity and lack of feeling.
From The Wall Street Journal • Mar. 26, 2026
At once menacing and clownish, Martin consistently tripped over his own incompetence, mendacity, and ignorance, ultimately dooming his chances of confirmation.
From Slate • May 10, 2025
He may invite passionate opposition from his foes, but his fans simply shrug at his misstatements, malapropisms and mendacity.
From Los Angeles Times • Jul. 30, 2024
“However, an odor of mendacity remains,” the judge wrote.
From Seattle Times • Mar. 15, 2024
We know merely what disasters his mendacity occasioned.
From "The Astonishing Life of Octavian Nothing, Traitor to the Nation, Volume II: The Kingdom on the Waves" by M.T. Anderson
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.
