A vigilante (from Spanish, Italian and Portuguese “vigilante”, which means "sentinel" or "watcher") is a person who practices or partakes in vigilantism, or undertakes public safety and retributive justice without commission.

Definition

According to political scientist Regina Bateson, vigilantism is the "the extralegal prevention, investigation, or punishment of offenses."[1] The definition has three components:

Extralegal: Vigilantism is done outside of the law (not necessarily in violation of the law)

Prevention, investigation, or punishment: Vigilantism requires specific actions, not just attitudes or beliefs

Offense: Vigilantism is a response to a perceived crime or violation of a authoritative norm

Other scholars have defined "collective vigilantism" as "group violence to punish perceived offenses to a community."