na-adjective, noun
Describes an unwavering will, spirit, or resolve that cannot be shaken. Often used in formal or literary contexts, especially in the phrase 不抜の意志 (indomitable will).
彼は不抜の意志で難局を乗り越えた。
He overcame the crisis with indomitable will.
不抜の精神があれば、どんな困難にも立ち向かえる。
With an unswerving spirit, you can face any hardship.