terrorist organization vs Irish Republican Army

terrorist organization and Irish Republican Army both are nouns.

Word	Noun	Adjective	Verb	Adverb
terrorist organization	Yes	No	No	No
Irish Republican Army	Yes	No	No	No

terrorist organization (noun)	Irish Republican Army (noun)
a political movement that uses terror as a weapon to achieve its goals	a militant organization of Irish nationalists who used terrorism and guerilla warfare in an effort to drive British forces from Northern Ireland and achieve a united independent Ireland