noun, na-adjective, noun which may take the genitive case particle 'no'
eternal and unchanging; permanence
A yojijukugo emphasizing absolute, timeless constancy. Often used in formal or literary contexts to describe principles, truths, or abstract qualities that never change.
この世界に永久不変なものはない。
Nothing in this world is eternal and unchanging.
彼は永久不変の愛を誓った。
He vowed eternal and unchanging love.
A yojijukugo composed of 永久 (eternal) and 不変 (unchanging). The exact historical derivation is uncertain, but it follows a common pattern of combining two two-character compounds to create an emphatic four-character idiom.