| sure(adjective, calm, close, strong, complete) |
| time-consuming |
| unfading(stable, fixed, constant, lasting, durable) |
| unremitting(adjective, determined, steady, stable, resolute) |
| unswerving(adjective, close, set, correct, firm) |
| deep-rooted(adjective, calm, strong, solid, substantial) |
| dispassionate(adjective, calm, cool, tolerant, excitability) |
| endurance(noun, increase, power, strength, line) |
| evergreen |
| irrevocable(adjective, certain, unquestionable, undisputable) |
| lifetime(adjective, durable) |
| long-range |
| loyal(adjective, close, correct, firm, honest) |
| never-ending(adjective, determined, constant, endless, infinite) |
| perpetuating(verb, increase, line, extension, persistence) |
| prolonged(adjective, great, deep, high, persistent) |
| rugged(adjective, strong, sound, fit, heavy) |
| set(adjective, calm, strong, secure, flat) |
| single-minded(adjective, firm, solid, determined, steady) |
| solid(adjective, calm, strong, sound, tough) |