The word “callous” is an adjective that describes someone who is emotionally hardened or insensitive, lacking sympathy or compassion towards others. It can also refer to a physical condition where the skin becomes toughened and thickened due to repeated friction or pressure.

Interesting fact: The word “callous” originated from the Latin word “callosus,” which means “hard-skinned.” This term was first used in the English language in the 16th century to describe the physical condition of hardened skin. Over time, its meaning expanded to include the emotional aspect of being insensitive or unfeeling.