from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Lying; untruthful.
  • adjective False; untrue: synonym: dishonest.

from The Century Dictionary.

  • Given to lying; speaking falsely; falsifying.
  • Having the character of a lie; false; untrue: as, a mendacious report; mendacious legends.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Given to deception or falsehood; lying.
  • adjective False; counterfeit; containing falsehood.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective of a person lying, untruthful or dishonest
  • adjective of a statement, etc. false or untrue

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adjective intentionally untrue
  • adjective given to lying


from The American Heritage® Dictionary of the English Language, 4th Edition

[From Latin mendācium, lie, from mendāx, mendāc-, mendacious.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle French mendacieux, from Latin mendācium ("lie, untruth"), from mendāx ("lying").


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  • Bernstein said:

    "In the case George W. Bush, the American system has obviously failed -- tragically -- about which we can talk more in a minute. But imagine the difference in our worldview today, had the institutions -- particularly of government -- done their job to insure that a mendacious and dangerous president (as has since been proven many times over, beyond mere assertion) be restrained in a war that has killed thousands of American soldiers, brought turmoil to the lives of millions, and constrained the goodwill towards the United States in much of the world."

    January 25, 2007

  • Loved this word ever since Big Daddy in Cat on a Hot Tin Roof said mendacity with such deliciousness!

    September 6, 2012