Something imperishable lasts a very long time, or feels as if it will last forever. Writers love it for fame, love, or art they hope will not die. The tidy idea inside the word is “cannot perish” — cannot die, rot, or be wiped away. Though actually, you will also meet it on food and supplies: imperishable food is food that does not go bad quickly, like dry rice or cans for emergencies. That use is more practical and less poetic, but it is the same word. It sounds a little bookish; in chat people more often say lasting, forever, or won't go bad.

不朽的（食物、物資則常說不會腐壞的）