terrorist group vs 15 May Organization

terrorist group and 15 May Organization both are nouns.

Word	Noun	Adjective	Verb	Adverb
terrorist group	Yes	No	No	No
15 May Organization	Yes	No	No	No

terrorist group (noun)	15 May Organization (noun)
a political movement that uses terror as a weapon to achieve its goals	a terrorist organization formed in 1979 by a faction of the Popular Front for the Liberation of Palestine but disbanded in the 1980s when key members left to join a faction of al-Fatah