Mendacious

/menˈdeɪʃəs/

adjective

not telling the truth; lying

The word 'mendacious' comes from the Latin word 'mendacium,' which means falsehood or lie. It is often used to describe someone who habitually tells lies or is not truthful.

Alexander I—the pacifier of Europe, the man who from his early years had striven only for his people’s welfare, the originator of the liberal innovations in his fatherland—now that he seemed to possess the utmost power and therefore to have the possibility of bringing about the welfare of his peoples—at the time when Napoleon in exile was drawing up childish and mendacious plans of how he would have made mankind happy had he retained power—Alexander I, having fulfilled his mission and feeling the hand of God upon him, suddenly recognizes the insignificance of that supposed power, turns away from it, and gives it into the hands of contemptible men whom he despises, saying only: “Not unto us, not unto us, but unto Thy Name! … I too am a man like the rest of you.

Leo Tolstoy

War and Peace

The latter perhaps wounds his vanity; but the former wounds his heart, his sympathy, which always says: “Ah, why would you also have as hard a time of it as I have?” 291 Man, a complex, mendacious, artful, and inscrutable animal, uncanny to the other animals by his artifice and sagacity, rather than by his strength, has invented the good conscience in order finally to enjoy his soul as something simple; and the whole of morality is a long, audacious falsification, by virtue of which generally enjoyment at the sight of the soul becomes possible.

Friedrich Nietzsche

Beyond Good and Evil

Unusual polysyllables of foreign origin she interpreted phonetically or by false analogy or by both: metempsychosis (met him pike hoses), alias (a mendacious person mentioned in sacred Scripture).

James Joyce

Ulysses