| enduring(adjective, certain, resolute, persistent, constant) |
| eternal |
| fast(adjective, intense, resolute, persistent, reliable) |
| fixed(adjective, resolute, persistent, dedicated, unwavering) |
| genuine(adjective, firm, honest, ardent, upright) |
| go-to(adjective, test, expert, reliable) |
| high-principled(good, strong, solid, steady, consistent) |
| immobile(adjective, intense, resolute, persistent, dedicated) |
| immovable(adjective, intense, resolute, persistent, dedicated) |
| in good faith(expression, adjective, idiom, firm, honest) |
| incorrupt(good, strong, solid, steady, consistent) |
| incorruptible(adjective, honest, loyal) |
| inexhaustible |
| inexorable(adjective, intense, resolute, persistent, dedicated) |
| infallible |
| inflexible(adjective, resolute, persistent, reliable, steadfast) |
| intense(adjective, resolute, persistent, dedicated, loyal) |
| intent(adjective, resolute, persistent, dedicated, unwavering) |
| invariable |
| lasting |