sulkiness vs resentment

sulkiness and resentment both are nouns.

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

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

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

sulkiness (noun)	resentment (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