old master vs Domenikos Theotocopoulos

old master and Domenikos Theotocopoulos both are nouns.

Word	Noun	Adjective	Verb	Adverb
old master	Yes	No	No	No
Domenikos Theotocopoulos	Yes	No	No	No

old master (noun)	Domenikos Theotocopoulos (noun)
a great European painter prior to 19th century	Spanish painter (born in Greece) remembered for his religious works characterized by elongated human forms and dramatic use of color (1541-1614)