| insensitive(adjective, mean, hard, cool, tough) |
| pitiless(adjective, mean, hard, tough, severe) |
| unemotional(adjective, mean, hard, cool, tough) |
| cold-blooded(adjective, person, mean, hard, cool) |
| hard-boiled(adjective, person, hard, careless, cold) |
| hardened(adjective, person, hard, tough, severe) |
| unbending(adjective, hard, firm, solid, careless) |
| apathetic(adjective, person, mean, hard, cool) |
| firm(adjective, hard, solid, cold, indifferent) |
| rigid(adjective, set, hard, firm, solid) |
| severe(adjective, mean, hard, tough, harsh) |
| stern(adjective, person, mean, severe, harsh) |
| uncaring(adjective, person, mean, hard, cool) |
| unmoved(adjective, mean, hard, cool, unpleasant) |
| unresponsive(adjective, person, mean, hard, cool) |
| unyielding(adjective, mean, hard, firm, harsh) |
| cruel(adjective, mean, hard, cool, tough) |
| frigid(adjective, mean, hard, cool, harsh) |
| obstinate(adjective, tenacious) |
| resolute(adjective, cold, indifferent, unyielding, tenacious) |