acerbity vs bitterness

acerbity and bitterness both are nouns.

Word	Noun	Adjective	Verb	Adverb
acerbity	Yes	No	No	No
bitterness	Yes	No	No	No

As nouns, acerbity and bitterness are synonyms defined as:

Other synonyms of acerbity include acrimony, jaundice, tartness, thorniness.

As nouns, bitterness is a hypernym of acerbity; that is, bitterness is a word with a broader meaning than acerbity:

Other hypernyms of acerbity include bitter.

acerbity (noun)	bitterness (noun)
a rough and bitter manner	the property of having a harsh unpleasant taste
a sharp sour taste	a rough and bitter manner
a sharp bitterness	the taste experience when quinine or coffee is taken into the mouth
	a feeling of deep and bitter anger and ill-will