liar

A liar is a person who makes statements that are deliberately false, with the intention to deceive others. Lying is typically contrasted with mistaken belief, where the person believes what they are saying is true.

The word lie comes from Old English leogan or leogan, meaning to lie or deceive; the agent noun liar was formed in English in the early modern period.

In ethics and psychology, lying is a behavior examined for its moral implications and cognitive aspects. Lies range from trivial to harmful, and cultures vary in what is tolerated. Some terms describe habitual deception, such as pathological lying.

Common types include white lies intended to spare feelings, lies of omission that withhold information, exaggerations, and fabrications. Motives include self-protection, avoidance of punishment, gaining advantage, or maintaining social harmony.

Consequences can erode trust in individuals and institutions. In legal contexts, lying under oath is perjury. Detecting deception is challenging; there is no universally reliable test to determine truth in everyday interaction, though inconsistencies, evidence, and corroboration are used.

The term also appears in philosophy as the liar paradox, a self-referential statement that creates a logical contradiction, as well as in literature and culture to describe falsehoods.