duke vs noble

duke and noble both are nouns.

Word	Noun	Adjective	Verb	Adverb
duke	Yes	No	No	No
noble	Yes	Yes	No	No

As nouns, noble is a hypernym of duke; that is, noble is a word with a broader meaning than duke:

Other hypernyms of duke include Lord, nobleman.

duke (noun)	noble (noun)
a British peer of the highest rank	a titled peer of the realm
a nobleman (in various countries) of high rank

duke (adjective)	noble (adjective)
	having or showing or indicative of high or elevated character
	of or belonging to or constituting the hereditary aristocracy especially as derived from feudal times
	impressive in size, manner, or appearance
	inert especially toward oxygen