Terrorism is, in its broadest sense, the use of intentionally indiscriminate violence (terror or fear) in order to achieve a political, religious, or ideological aim. It is classified as fourth-generation warfare and as a violent crime. In modern times, it is considered a major threat to society and therefore illegal under anti-terrorism laws in most jurisdictions. It is also considered a war crime under the laws of war when used to target non-combatants, such as civilians, neutral military personnel, or enemy prisoners of war.
A broad array of political organizations have practiced it to further their objectives. It has been practiced by both right-wing and left-wing political organizations, nationalist groups, religious groups, revolutionaries, and ruling governments. The symbolism can exploit human fear to help achieve these goals.
According to data from the Global Database, more than 61,000 incidents of non-state terrorism claiming over 140,000 lives have been recorded from 2000 to 2014.