German vs Berliner

German and Berliner both are nouns.

Word	Noun	Adjective	Verb	Adverb
German	Yes	Yes	No	No
Berliner	Yes	No	No	No

As nouns, Berliner is a hyponym of German; that is, Berliner is a word with a more specific, narrower meaning than German:

Other hyponyms of German include Teuton, East German, Boche, Hun, Jerry, Kraut, Krauthead, Prussian, Bavarian.

German (noun)	Berliner (noun)
the standard German language; developed historically from West Germanic	an inhabitant of Berlin
a person of German nationality

German (adjective)	Berliner (adjective)
of or pertaining to or characteristic of Germany or its people or language