Duplicity is a formal word that refers to dishonest behavior meant to trick or deceive someone. It is the quality or state of being twofold or double. Duplicity can manifest in various forms, such as speaking or acting in two different ways to different people concerning the same matter, double-dealing, or deliberate deceptiveness in behavior or speech. The word "duplicity" comes from the Latin word "duplex," which means "double" or "twofold". Someone who shows duplicity is two-faced, maybe showing one side in public and another in private, or is just a liar, saying something known to be untrue or misleading. A fraud uses duplicity to gain something with false promises, and someone described as "fake" might use duplicity just to fit in or be accepted.