What term names a false online identity used for deception?

A false online identity used for deception is called a sock puppet, or sock puppet account.

A sock puppet is an identity created or controlled by someone who wants to conceal their real identity or pretend that another independent person exists. It can be used to praise a product, manipulate a discussion, influence votes, evade a ban, or attack an opponent. The term is a metaphor for a hand puppet operated by an unseen puppeteer.

Sock puppetry is broader than simply using a nickname. A pseudonym can be legitimate when its user is open about being one person behind it; deception and the appearance of an independent identity are central to the sock-puppet idea. Multiple deceptive accounts used to manufacture apparent support are sometimes compared with a Sybil attack.

The practice predates the internet: people have used pseudonyms to review or promote their own work. Online platforms may investigate suspected sock puppets through patterns such as writing style, activity timing, and technical account links.