noun, plural men·dac·i·ties for 2.

the quality of being mendacious; untruthfulness; tendency to lie.
an instance of lying; falsehood.

Origin of mendacity

1640–50; < Late Latin mendācitās falsehood, equivalent to Latin mendāci- (stem of mendāx) given to lying, false + -tās -ty2
Can be confusedmendacity mendicity

Synonyms for mendacity Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for mendacity

Contemporary Examples of mendacity

Historical Examples of mendacity

  • That, and his career of mendacity, would start at breakfast.

    The Cosmic Computer

    Henry Beam Piper

  • And Harry had the mendacity to assure her that this was a favorite habit of mine.

  • Because Falsehood was blemished in having no feet, she was called mendacium or mendacity.

  • The yellow-press surpassed themselves in clamor and mendacity.

    Theodore Roosevelt

    Edmund Lester Pearson

  • This concluding paragraph is simply a tissue of mendacity and absurdity.

British Dictionary definitions for mendacity


noun plural -ties

the tendency to be untruthful
a falsehood
Derived Formsmendacious (mɛnˈdeɪʃəs), adjectivemendaciously, adverbmendaciousness, noun

Word Origin for mendacity

C17: from Late Latin mendācitās, from Latin mendāx untruthful
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for mendacity

"tendency to lie," 1640s, from Middle French mendacité and directly from Late Latin mendacitas "falsehood, mendacity," from Latin mendax "lying; a liar" (see mendacious).

Online Etymology Dictionary, © 2010 Douglas Harper