Synonyms and related words :
abiding, amaranthine, continuing, continuous, deathless, embalmed, ever-fresh, everlasting, fadeless, frozen, immortal, imperishable, impregnable, incorruptible, indefatigable, indelible, indestructible, ineffaceable, ineradicable, inexpugnable, inextinguishable, interminable, invincible, invulnerable, never-dying, nonperishable, persistent, quenchless, remaining, staying, steady, sticking, sustained, unceasing, undampable, undestroyable, unfading, unquenchable, unremitting