| unalterable(adjective, strong, severe, flat, harsh) |
| unbending(adjective, strong, flat, harsh, certain) |
| unbroken(adjective, quiet, direct, smooth, right) |
| unflinching(adjective, strong, flat, harsh, certain) |
| dependable(adjective, regular, even, constant, uniform) |
| dogged(adjective, firm, harsh, solid, cruel) |
| monolithic(adjective, even, rigid, inflexible, reliable) |
| monotonous(adjective, quiet, soft, gentle, flat) |
| rigorous(adjective, severe, harsh, solid, exact) |
| unbent(adjective, straight, straightness) |
| close |
| consonant(adjective, even, rigid, inflexible, reliable) |
| equable(adjective, quiet, soft, gentle, flat) |
| flat(adjective, quiet, strong, direct, smooth) |
| lasting(adjective, continuous) |
| linear(adjective, direct, smooth, right, solid) |
| nonstop(adjective, smooth, right, solid, level) |
| obstinate(adjective, intense, deliberate, determined, resolute) |
| perpetual(adjective, continuous) |
| resolved(adjective, strong, flat, certain, determined) |