national leader vs Demosthenes

national leader and Demosthenes both are nouns.

Word	Noun	Adjective	Verb	Adverb
national leader	Yes	No	No	No
Demosthenes	Yes	No	No	No

national leader (noun)	Demosthenes (noun)
a person who is a respected leader in national or international affairs	Athenian statesman and orator (circa 385-322 BC)