| long-standing(adjective, continue, strain, firmness, labour) |
| fast(adjective, strong, tough, strain, firm) |
| refractory(adjective, strain, firmness, labour, hardiness) |
| unalterable(adjective, strong, strain, flat, certain) |
| staying(adjective, strain, firmness, labour, hardiness) |
| sustained(adjective, strain, firmness, constant, continuous) |
| settled(adjective, strong, strain, flat, firm) |
| stout(adjective, strain, firmness, labour, hardiness) |
| quiescent(adjective, strain, firmness, labour, hardiness) |
| resist(verb, adjective, strain, firmness, labour) |
| seamless(adjective, strain, firmness, continuous, labour) |
| stationary(adjective, strain, firmness, labour, hardiness) |
| substantial(adjective, strain, firmness, labour, hardiness) |
| tolerant(adjective, quiet, understanding, gentle, strain) |
| robust(adjective, strain, firmness, labour, hardiness) |
| stabile(adjective, strain, steady, regular, firmness) |
| tight(adjective, strain, firmness, labour, hardiness) |
| stubborn(adjective, characteristic, quality, stubbornness, determined) |
| tenacious(adjective, strong, tough, flat, firm) |
| continual(adjective, continue, certain, determined, usual) |