EU vs international organization

EU and international organization both are nouns.

Word	Noun	Adjective	Verb	Adverb
EU	Yes	No	No	No
international organization	Yes	No	No	No

As nouns, international organization is a hypernym of EU; that is, international organization is a word with a broader meaning than EU:

EU: an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members
international organization: an international alliance involving many different countries

EU (noun)	international organization (noun)
an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members	an international alliance involving many different countries