callosity vs hardening

callosity and hardening both are nouns.

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

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

callosity: an area of skin that is thick or hard from continual pressure or friction (as the sole of the foot)
hardening: abnormal hardening or thickening of tissue

callosity (noun)	hardening (noun)
devoid of passion or feeling; hardheartedness	the act of making something harder (firmer or tighter or more compact)
an area of skin that is thick or hard from continual pressure or friction (as the sole of the foot)	the process of becoming hard or solid by cooling or drying or crystallization
	abnormal hardening or thickening of tissue