Callous means ‘not feeling or showing any concern about the problems or suffering of other people: “He made a callous remark about those who were killed in terrorist remark and how it meant that the population of the country reduced in such attacks.”
Effectively, a callous person is an emotionally hardened; one not given to feelings.
Callus, on the other hand, a hard, thickened place on the skin; especially, on the hands and feet: “Callu on the feet can be painful.”
