| persistent(adjective, strain, firmness, labour, hardiness) |
| strong(adjective, calm, clear, strong, hard) |
| stable(adjective, strong, hard, complete, secure) |
| firm(noun, adjective, calm, strong, hard) |
| hard(adjective, strong, reasonable, strain, honest) |
| consistent(adjective, clear, reasonable, strain, sensible) |
| stiff(adjective, strong, strain, solid, firmness) |
| unfluctuating(adjective, calm, strong, secure, strain) |
| substantial(adjective, calm, strong, hard, complete) |
| robust(adjective, health, strong, complete, secure) |
| stout(adjective, calm, strong, tough, right) |
| fast(adjective, calm, strong, secure, tough) |
| durable(adjective, calm, strong, secure, tough) |
| steady(adjective, calm, quiet, strong, secure) |
| well-balanced(adjective, strain, sensible, equal, firmness) |
| conservative(adjective, strain, firmness, labour, hardiness) |
| tight(adjective, good, strong, hard, secure) |
| rigid(adjective, strain, firmness, labour, conformity) |
| steadfast(adjective, calm, strong, secure, easy) |
| lasting(adjective, strain, firmness, labour, hardiness) |