S: (n) Ku Klux Klan, Klan, KKK (a secret society of white Southerners in the United States; was formed in the 19th century to resist the emancipation of slaves; used terrorist tactics to suppress Black people)
S: (n) terrorism, act of terrorism, terrorist act (the calculated use of violence (or the threat of violence) against civilians in order to attain goals that are political or religious or ideological in nature; this is done through intimidation or coercion or instilling fear)