Terrorism is defined as any act intended to cause terror, often with political objectives, and has been historically associated with both state and non-state actors. The term originates from the French 'terrorisme' during the Reign of Terror in the late 18th century, evolving to generally refer to violent acts aimed at civilians to intimidate for political motives. Various international and legal definitions of terrorism remain contentious and fragmented, complicating unified efforts to combat it.