An impersonator is someone who imitates or copies the behavior or actions of another. There are many reasons for impersonating someone:

• Living history: After close study of some historical figure, a performer may dress and speak "as" that person for an audience. Such historical interpretation may be a scripted dramatic performance like Mark Twain Tonight! or an unscripted interaction while staying in character.

• Entertainment: An "impressionist" impersonates well-known figures in order to entertain an audience. Especially popular objects of impersonation are Elvis Presley, Michael Jackson and Madonna. Other uses of impersonation for entertainment include male drag queens
• Crime: As part of a criminal act such as identity theft. This is usually where the criminal is trying to assume the identity of another, in order to commit fraud, such as accessing confidential information, or to gain property not belonging to them. Also known as social engineering and impostors.
• Decoys, used as a form of protection for political and military figures. This involves an impersonator who is employed to perform during public appearances, to mislead observers.
• Sowing discord, causing people to fight, or dislike each other for social, business or political gain.