terrorist act vs Sicilian Mafia

terrorist act and Sicilian Mafia both are nouns.

Word	Noun	Adjective	Verb	Adverb
terrorist act	Yes	No	No	No
Sicilian Mafia	Yes	No	No	No

terrorist act (noun)	Sicilian Mafia (noun)
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	a secret terrorist group in Sicily; originally opposed tyranny but evolved into a criminal organization in the middle of the 19th century