mendacity

Etymology

Comes from Late Latin mendacitas, from Latin mendāx (“deceitful, deceptive, lying”) plus -itās (a suffix forming nouns of state). Mendāx itself derives from mentior (“to deceive, lie”), from mēns, mentis (“mind; intellect; judgment, reasoning”), from Proto-Indo-European *méntis (“thought”), plus -āx (a suffix forming adjectives of tendency or inclination) — or alternatively from Proto-Indo-European *mend- (“to fault”). By surface analysis, it is Latin mendāc- plus -ity.