- having calluses; having skin made tough and dense through use
- emotionally hardened
- make insensitive or callous; deaden thoughts or morals
- Hardened; indurated.
- Hardened in mind; insensible; unfeeling; unsusceptible.
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.
The police showed callous disregard for innocent lives.