Literary or formal noun meaning something that never fades or wears away. Most often encountered in the set phrase 不磨の (e.g., 不磨の価値, 不磨の真理).
This work is said to have permanent value.
eternal; everlasting; immortal
everlasting; immortal; enduring forever
From 不 (not) + 磨 (polish, wear away), literally 'unpolished' or 'unworn', extended to mean something that endures without deterioration.