prince vs blue blood

prince and blue blood both are nouns.

Word	Noun	Adjective	Verb	Adverb
prince	Yes	No	No	No
blue blood	Yes	No	No	No

As nouns, blue blood is a hypernym of prince; that is, blue blood is a word with a broader meaning than prince:

prince: a male member of a royal family other than the sovereign (especially the son of a sovereign)
blue blood: a member of the aristocracy

Other hypernyms of prince include aristocrat, patrician, adult male, man.

prince (noun)	blue blood (noun)
a male member of a royal family other than the sovereign (especially the son of a sovereign)	a member of the aristocracy