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Synonyms

mendacious

American  
[men-dey-shuhs] / mɛnˈdeɪ ʃəs /

adjective

  1. telling lies, especially habitually; dishonest; lying; untruthful.

    a mendacious person.

    Antonyms:
    veracious
  2. false or untrue.

    a mendacious report.

    Antonyms:
    veracious

Other Word Forms

  • mendaciously adverb
  • mendaciousness noun
  • unmendacious adjective
  • unmendaciously adverb

Etymology

Origin of mendacious

1610–20; < Latin mendāci- ( mendacity ) + -ous

Explanation

A mendacious person is one who tells lies habitually and intentionally. Don't get stuck at the water cooler or bus stop next to someone you consider mendacious! People may tell "white lies" if they forgot your birthday or really don't like your new haircut, but if you catch someone intentionally manipulating you with a falsehood, that person is just plain mendacious. So think of the most deceptive, insincere, perfidious, duplicitous, false person you've ever met, and then add the word mendacious to that list.

Keep Reading on Vocabulary.com

Vocabulary lists containing mendacious

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.

Everyone understands there’s a truthful side and a mendacious side.

From Slate • Feb. 14, 2025

He posted on X "That speech of Robert Jenrick's was lazy, mendacious, simplistic tripe."

From BBC • Oct. 6, 2024

The office of Prime Minister Benjamin Netanyahu said in a statement that the report was "mendacious and without any foundation whatsoever".

From Reuters • Apr. 9, 2023

If that’s so, brace yourself for an outpouring of misleading and mendacious ads.

From Los Angeles Times • Oct. 17, 2022

“Especially,” said Charles, “when the batty bandleader is a disingenuous and mendacious charlatan.”

From "Mr. Lemoncello's Library Olympics" by Chris Grabenstein