callous

Emotionally hardened; unfeeling and indifferent to the suffering/feelings of others.

She was so callous that she could criticise a cancer patient for wearing a wig.

Re-watching some of the audition rounds of these shows now, you're struck by how callous the judges' comments often were, and how they presented a cruel spectacle in which the audience were set up to laugh at the "deluded" members of the public who believed they could sing.

Having calluses, or relating to calluses.

Alternative form of callus.

Hanson was beginning to feel annoyance at the suddenly cocksure and unsympathetic girl, but he stood fully erect and flexed his muscles. There wasn't even a trace of bedsoreness, though he had been flat on his back long enough to grow callouses.

Alternative form of callus.