dullness vs callosity

dullness and callosity both are nouns.

Word	Noun	Adjective	Verb	Adverb
dullness	Yes	No	No	No
callosity	Yes	No	No	No

As nouns, callosity is a hypernym of dullness; that is, callosity is a word with a broader meaning than dullness:

Other hypernyms of dullness include callousness, hardness, insensibility, unfeelingness.

dullness (noun)	callosity (noun)
lack of sensibility	devoid of passion or feeling; hardheartedness
without sharpness or clearness of edge or point	an area of skin that is thick or hard from continual pressure or friction (as the sole of the foot)
the quality of lacking interestingness
a lack of visual brightness
the quality of being slow to understand