Wiktionary
callusing
vb. (present participle of callus English)
Usage examples of "callusing".
Nor is there much in the way of callusing on the heel and along the sides.
She could feel its warmth, and a heavy layer of callusing, through her three layers of sleeves.
Healing the feet, toughing them up, callusing them, that was easy enough.
Likewise the dryness and pronounced callusing of fingers and toes that I had already noticed.