1 undying, eternal, deathless, everlasting, eternal, imperishable, sempiternal, never-ending, endless, ceaseless, perpetual, timeless, constant, permanent, indestructible:
Did the Egyptian pharaohs believe themselves immortal?
2 divine, heavenly, godlike:
The immortal wisdom of God guides man.
3 remembered, celebrated, unfading, famous, renowned, classic, lauded, praised, honoured, timeless:
The immortal writings of Shakespeare inspire us still.
4 Olympian, god or goddess; hero or heroine, legend, genius, great:
To be sure, we must consider Bach as one of the immortals.