| resistant(adjective, strong, tough, strain, fit) |
| unshakable(adjective, mean, strong, hard, complete) |
| solid(adjective, calm, good, close, set) |
| staying(adjective, strain, firmness, labour, hardiness) |
| impregnable(adjective, strain, true, firmness, constant) |
| perpetual(adjective, strain, determined, familiar, steady) |
| quiescent(adjective, strain, firmness, labour, hardiness) |
| stabile(adjective, calm, strong, secure, strain) |
| sustained(adjective, strain, firmness, persistent, continuous) |
| conservative(adjective, moderate, strain, firmness, cautious) |
| insistent(adjective, set, determined, steady, resolute) |
| long-standing(adjective, strain, firmness, labour, hardiness) |
| resilient(adjective, strain, firmness, labour, hardiness) |
| stabilized(adjective, strain, firmness, labour, hardiness) |
| tenable(adjective, strain, firmness, labour, hardiness) |
| well-balanced(adjective, strain, firmness, labour, hardiness) |
| abundant(adjective, strain, firmness, labour, hardiness) |
| immune(adjective, strain, firmness, safe, labour) |
| non-fluctuating(adjective, strain, firmness, labour, hardiness) |
| proof(adjective, strain, firmness, labour, hardness) |