nobility vs knighthood

nobility and knighthood both are nouns.

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

As nouns, knighthood is a hyponym of nobility; that is, knighthood is a word with a more specific, narrower meaning than nobility:

Other hyponyms of nobility include noblesse, baronage, peerage, baronetage, samurai.

nobility (noun)	knighthood (noun)
the quality of elevation of mind and exaltation of character or ideals or conduct	aristocrats holding the rank of knight
a privileged class holding hereditary titles
the state of being of noble birth