An impersonator is someone who imitates or copies the behavior or actions of another. There are many reasons for someone to be an impersonator, some common ones being as follows:

• Legally: An entertainer impersonates a celebrity, generally for entertainment, and makes fun of their recent scandals or known behavior patterns. Entertainers who impersonate multiple celebrities as part of their act, can be sorted out to impressionists and celebrity impersonators.
• Illegally: 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.
• Political decoy, used as a form of protection for political and military figures. This involves an impersonator who is employed (or forced) to perform during public appearances, to mislead observers. This is also legal.
• Causing people to fight, or dislike each other for social, business or political gain.