A lie is an assertion that is believed to be false, typically used with the purpose of deceiving or misleading someone. The practice of communicating lies is called lying. A person who communicates a lie may be termed a liar. Lies can be interpreted as deliberately false statements or misleading statements, though not all statements that are literally false are considered lies – metaphors, hyperboles, and other figurative rhetoric are not intended to mislead, while lies are explicitly meant for literal interpretation by their audience. Lies may also serve a variety of instrumental, interpersonal, or psychological functions for the individuals who use them.

Deception is an act or statement that misleads, hides the truth, or promotes a belief, concept, or idea that is not true. This occurs when a deceiver uses information against a person to make them believe an idea is true. Deception can be used with both verbal and nonverbal messages. The person creating the deception knows it to be false while the receiver of the message has a tendency to believe it. It is often done for personal gain or advantage. Deception can involve dissimulation, propaganda and sleight of hand as well as distraction, camouflage or concealment. There is also self-deception, as in bad faith. It can also be called, with varying subjective implications, beguilement, deceit, bluff, mystification, ruse, or subterfuge.