| hard and fast(expression, adjective, idiom, set, strict) |
| heartless(adjective, mean, hard, harsh, careless) |
| icy(adjective, severe) |
| inhuman(adjective, harsh, cruel, determined, fierce) |
| meticulous(adjective, severe) |
| monolithic(adjective, solid, normal, even, rigid) |
| ossified(adjective, firm, solid, determined, normal) |
| rocky(adjective, set, strong, hard, firm) |
| rough(adjective, person, strong, hard, tough) |
| straight(adjective, direct, right, moderate, level) |
| taut(adjective, hard, rough, firm, harsh) |
| uncontrollable |
| unfeeling(adjective, mean, hard, tough, severe) |
| unmoving |
| unruly(adjective, obstinate, stubborn, willful) |
| unsusceptible(adjective, hard, careless, indifferent, cruel) |
| unvarying(adjective, set, regular, fixed, even) |
| wayward(adjective, obstinate, stubborn, willful) |
| balky(adjective, tough, firm, unreasonable, obstinate) |
| cast-iron(intent, hard-and-fast) |