| insensible(adjective, strong, hard, tough, severe) |
| intolerant(adjective, hard, severe, cold, indifferent) |
| oppressive(adjective, severe, severity) |
| recalcitrant(adjective, tough, firm, difficult, violent) |
| rocky(adjective, difficult, troubled, inflexible, unyielding) |
| single-minded(adjective, tough, firm, harsh, cruel) |
| stonyhearted(adjective, attitude) |
| stringent(adjective, tough, severe, harsh, cruel) |
| unchangeable(adjective, strong, hard, definite, inflexible) |
| unresponsive(adjective, person, mean, hard, cool) |
| unsparing(adjective, close, strong, hard, tough) |
| brutal(adjective, mean, hard, tough, severe) |
| cold-hearted(adjective, hard, tough, severe, attitude) |
| coldhearted(adjective, hard, cold, indifferent, detached) |
| demanding(adjective, severe) |
| frigid(adjective, mean, hard, cool, harsh) |
| graceless(shameless, impenitence) |
| icy(adjective, mean, hard, cool, tough) |
| incorrigible(adjective, vice) |
| insensate(adjective, hard, tough, severe, careless) |