men·​da·​cious men-ˈdā-shəs How to pronounce mendacious (audio)
: given to or characterized by deception or falsehood or divergence from absolute truth
mendacious tales of his adventures
mendaciously adverb
mendaciousness noun

Did you know?

Mendacious and lying have very similar meanings, but the two are not interchangeable. Mendacious is more formal and literary, suggesting a deception harmless enough to be considered somewhat bland. Lying is more blunt, accusatory, and often confrontational. You might yell, "You lying rat!" in an argument, but you would most likely stick to the more diplomatic, "Aren't you being somewhat mendacious?" in a business meeting. Mendacious can also imply habitual untruthfulness, whereas lying is more likely to be used to identify specific instances of dishonesty.

Choose the Right Synonym for mendacious

dishonest, deceitful, mendacious, untruthful mean unworthy of trust or belief.

dishonest implies a willful perversion of truth in order to deceive, cheat, or defraud.

a swindle usually involves two dishonest people

deceitful usually implies an intent to mislead and commonly suggests a false appearance or double-dealing.

the secret affairs of a deceitful spouse

mendacious may suggest bland or even harmlessly mischievous deceit and when used of people often suggests a habit of telling untruths.

mendacious tales of adventure

untruthful stresses a discrepancy between what is said and fact or reality.

an untruthful account of their actions

Example Sentences

Indeed, the racist and Malthusian elements in Darwin's work are subjects on which the new secularists are either silent, delicate, or mendacious. Eugene McCarraher, Commonweal, 15 June 2007
A choice item in the collection of mendacious stories that were circulated about Columbus after his death is this. Columbus lost himself on the way to Hispaniola, and only by virtue of letters and pilots sent by Martín Alonso did he manage to find the island and join Pinta. Samuel Eliot Morison, Admiral of the Ocean Sea, 1942
Mildred had become great friends with her and had given her an elaborate but mendacious account of the circumstances which had brought her to the pass she was in. W. Somerset Maugham, Of Human Bondage, 1915
The newspaper story was mendacious and hurtful. that tabloid routinely publishes the most moronically mendacious stories about celebrities
Recent Examples on the Web So why not just ignore this latest outburst from the mendacious Muscovite? Eric Berger, Ars Technica, 8 May 2023 Many less attractive traits are also recorded: Charles could be uncommunicative and dilatory, evasive and mendacious, refractory, vindictive, obstinate, even outright wicked, though self-delusive about the motives of others. R.j.w. Evans, The New York Review of Books, 11 June 2020 Just as some claims made in business are so self-evidently fictitious that even the most shameless of hucksters will recoil from articulating them, so some propositions advanced in politics are so dishonest that even the most mendacious politician will avoid association with them. Gerard Baker, WSJ, 1 Aug. 2022 Letters written while events were unfolding appear side by side with memoirs, some thoughtful and others mendacious, written decades later. Gary Saul Morson, The New York Review of Books, 15 June 2021 That was bad, but his mendacious campaign against Proposition 30 is of far more consequence. Liza Featherstone, The New Republic, 29 Nov. 2022 In its mendacious rendering of the past, Putin’s historical screed tapped deep currents of imperialist nostalgia and the enduring belief that the lands to Russia’s west were its historical patrimony. Daniel Beer, Washington Post, 29 Sep. 2022 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'mendacious.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


Latin mendac-, mendax — more at amend

First Known Use

1616, in the meaning defined above

Time Traveler
The first known use of mendacious was in 1616


Dictionary Entries Near mendacious

Cite this Entry

“Mendacious.” Dictionary, Merriam-Webster, Accessed 3 Jun. 2023.

Kids Definition


men·​da·​cious men-ˈdā-shəs How to pronounce mendacious (audio)
: apt to tell lies
mendaciously adverb

More from Merriam-Webster on mendacious

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