| hard(adjective, tough, severe, indifferent, cruel) |
| hard-hearted(adjective, hard, tough, severe, cold) |
| hard as nails(expression, adjective, idiom, hard, indifferent) |
| hardened(adjective, hard, tough, severe, indifferent) |
| hardhearted(adjective, hard, indifferent, cruel, unsympathetic) |
| heartless(adjective, hard, tough, severe, indifferent) |
| icy(adjective, hard, tough, severe, cold) |
| imperceptive(adjective, hard, indifferent, unkind, unresponsive) |
| inanimate(adjective, hard, tough, severe, cold) |
| incurious(adjective, hard, indifferent, unkind, unresponsive) |
| inhuman(adjective, hard, tough, severe, cold) |
| insensate(adjective, hard, tough, severe, cold) |
| insensible(adjective, hard, tough, severe, cold) |
| insusceptible(adjective, hard, insensitive, unsusceptible) |
| iron-hearted(adjective, hard, tough, severe, cold) |
| merciless(adjective, hard, tough, severe, cold) |
| numb(adjective, hard, tough, severe, cold) |
| obdurate(adjective, hard, tough, severe, cold) |
| obtuse(adjective, hard, indifferent, unkind, unresponsive) |
| pitiless(adjective, hard, tough, severe, cold) |