c. 1400, "hardened," in the physical sense, from Latin callosus "thick-skinned," from callus, callum "hard skin" (see callus). The figurative sense of "unfeeling" appeared in English by 1670s. Related: Callously; callousness.
例文
1. He is callous about the safety of his workers.
彼は彼の労働者の安全に少しも関心がない.
2.The colonists massacred thousands of natives with brutal and callous force.