Bart vs blue blood

Bart and blue blood both are nouns.

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

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

Bart: a member of the British order of honor; ranks below a baron but above a knight
blue blood: a member of the aristocracy

Other hypernyms of Bart include aristocrat, patrician.

Bart (noun)	blue blood (noun)
a member of the British order of honor; ranks below a baron but above a knight	a member of the aristocracy