German capital vs Berlin

German capital and Berlin both are nouns.

Word	Noun	Adjective	Verb	Adverb
German capital	Yes	No	No	No
Berlin	Yes	No	No	No

As nouns, German capital and Berlin are synonyms defined as:

German capital and Berlin: capital of Germany located in eastern Germany

German capital (noun)	Berlin (noun)
capital of Germany located in eastern Germany	capital of Germany located in eastern Germany
	United States songwriter (born in Russia) who wrote more than 1500 songs and several musical comedies (1888-1989)