| fast(adjective, strain, firmness, labour, hardiness) |
| durable(adjective, strain, firmness, labour, hardiness) |
| resilient(adjective, strain, firmness, labour, hardiness) |
| substantial(adjective, strain, firmness, labour, hardiness) |
| tenable(adjective, strain, firmness, labour, hardiness) |
| unalterable(adjective, hard, strain, rough, harsh) |
| withstanding(adjective, strain, firmness, labour, hardiness) |
| contrary(adjective, tough, difficult, cross, wild) |
| immune(adjective, strain, firmness, labour, hardiness) |
| invariable(adjective, strain, firmness, labour, hardiness) |
| rebellious(adjective, tough, firm, negative, obstinate) |
| rock-solid(adjective, strain, firmness, labour, hardiness) |
| stout(adjective, strain, firmness, labour, hardiness) |
| tight(adjective, strain, firm, solid, firmness) |
| fractious(adjective, control, order, cross, resist) |
| resist(verb, adjective, strain, firmness, labour) |
| perverse(adjective, mean, tough, difficulty, firm) |
| insubordinate(adjective, tough, firm, negative, hostile) |
| wayward(adjective, tough, difficult, violent, wild) |
| defiant(adjective, persistent, obstinate, insistent, dogged) |