Mendacity

Deception, beguilement, deceit, bluff, mystification, ruse, or subterfuge is the act of propagating beliefs in things that are not true, or not the whole truth (as in half-truths or omission). 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.

Deception is a major relational transgression that often leads to feelings of betrayal and distrust between relational partners. Deception violates relational rules and is considered to be a negative of expectations. Most people expect friends, relational partners, and even strangers to be truthful most of the time. If people expected most conversations to be untruthful, talking and communicating with others would require distraction and misdirection to acquire reliable information. A significant amount of deception occurs between some romantic and relational partners.

Deceit and dishonesty can also form grounds for civil litigation in tort, or contract law (where it is known as misrepresentation or fraudulent misrepresentation if deliberate), or give rise to criminal prosecution for fraud. It also forms a vital part of psychological warfare in denial and deception.

Deception includes several types of communications or omissions that serve to distort or omit the complete truth. Examples of deception range from false statements to misleading claims in which relevant information is omitted, leading the receiver to infer false conclusions. For example, a claim that 'sunflower oil is beneficial to brain health due to the presence of omega-3 fatty acids' may be misleading, as it leads the receiver to believe sunflower oil will benefit brain health more so than other foods. In fact, sunflower oil is relatively low in omega-3 fatty acids and is not particularly good for brain health, so while this claim is technically true, it leads the receiver to infer false information. Deception itself is intentionally managing verbal and/or nonverbal messages so that the message receiver will believe in a way that the message sender knows is false. Intent is critical with regard to deception. Intent differentiates between deception and an honest mistake. The Interpersonal Deception Theory explores the interrelation between communicative context and sender and receiver cognitions and behaviors in deceptive exchanges.

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Wikipedia