Callus (noun) – Hard thickened area on the skin or a thickening of area on skin. A callus could form around a break in a bone.
Callous (adjective) – Thickened or hardened. It can also mean feeling no emotion.
Callously is an adverb.
Callousness is a noun.
Both callus and callous can be used as verbs.
periosteal callus formation
Send in the words you have for callus and callous.