| callous(noun, adjective, person, hard, cool) |
| hard(adjective, tough, severe, firm, attitude) |
| hard-boiled(noun, adjective, person, hard, attitude) |
| inured(noun, adjective, set, strong, hard) |
| toughened(noun, verb, adjective, set, hard) |
| unfeeling(noun, adjective, hard, cool, attitude) |
| obdurate(adjective, person, hard, tough, severe) |
| tempered(verb, adjective, strengthened) |
| tough(noun, adjective, strong, hard, severe) |
| insensitive(noun, adjective, hard, tough, severe) |
| set(verb, adjective, hard, tough, firm) |
| solidified(verb, adjective, set, hard, tough) |
| stony(adjective, person, hard, tough, severe) |
| uncompassionate(adjective, person, hard, tough, severe) |
| cold-blooded(adjective, person, hard, cool, tough) |
| shameless(adjective, hard, tough, harsh, rude) |
| stiff(adjective, hard, tough, firm, solid) |
| heartless(adjective, hard, cool, tough, severe) |
| inflexible(adjective, person, hard, tough, firm) |
| rigid(adjective, strong, hard, tough, firm) |