mendacity

noun, plural men·dac·i·ties for 2.

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

noun plural -ties

1. the tendency to be untruthful
2. a falsehood

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