samurai vs nobility

samurai and nobility both are nouns.

Word	Noun	Adjective	Verb	Adverb
samurai	Yes	No	No	No
nobility	Yes	No	No	No

As nouns, nobility is a hypernym of samurai; that is, nobility is a word with a broader meaning than samurai:

Other hypernyms of samurai include aristocracy.

samurai (noun)	nobility (noun)
feudal Japanese military aristocracy	the quality of elevation of mind and exaltation of character or ideals or conduct
a Japanese warrior who was a member of the feudal military aristocracy	a privileged class holding hereditary titles
	the state of being of noble birth