Englishundying
adjective
his undying devotion to the club:
abiding, lasting, enduring, permanent, continuing, constant, perennial, infinite;
unceasing, perpetual, ceaseless, incessant, unending, never-ending, unfading;
immortal, eternal, deathless, never-dying;
indestructible, imperishable, inextinguishable;
undiminished, undestroyed;
rare sempiternal.
▷antonyms transient, ephemeral; mortal.
undying Oxford Dictionary of English