Greek capital vs capital of Greece

Greek capital and capital of Greece both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greek capital	Yes	No	No	No
capital of Greece	Yes	No	No	No

As nouns, Greek capital and capital of Greece are synonyms defined as:

Greek capital and capital of Greece: the capital and largest city of Greece; named after Athena (its patron goddess)

Other synonyms of Greek capital include Athens, Athinai.

Greek capital (noun)	capital of Greece (noun)
the capital and largest city of Greece; named after Athena (its patron goddess)	the capital and largest city of Greece; named after Athena (its patron goddess)