sulkiness vs rancor

sulkiness and rancor both are nouns.

Word	Noun	Adjective	Verb	Adverb
sulkiness	Yes	No	No	No
rancor	Yes	No	No	No

As nouns, rancor is a hypernym of sulkiness; that is, rancor is a word with a broader meaning than sulkiness:

Other hypernyms of sulkiness include bitterness, gall, rancour, resentment.

sulkiness (noun)	rancor (noun)
a sullen moody resentful disposition	a feeling of deep and bitter anger and ill-will
a feeling of sulky resentment
a mood or display of sullen aloofness or withdrawal