Iron Duke vs national leader

Iron Duke and national leader both are nouns.

Word	Noun	Adjective	Verb	Adverb
Iron Duke	Yes	No	No	No
national leader	Yes	No	No	No

Iron Duke (noun)	national leader (noun)
British general and statesman; he defeated Napoleon at Waterloo; subsequently served as Prime Minister (1769-1852)	a person who is a respected leader in national or international affairs