Definition of Callous: Callous (adjective): Showing or having an insensitive and cruel disregard for others; emotionally hardened. Synonyms: heartless, unfeeling, insensitive, indifferent Antonyms: compassionate, kind, empathetic, tender Memory Tip: Think of “callous” as “callus”—just like a callus on your hand is tough and insensitive, a callous person has a tough and unfeeling heart. Conversation and…