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).
He overcame the crisis with indomitable will.
With an unswerving spirit, you can face any hardship.
indomitable perseverance; invincible fortitude
determined; steadfast; unshakable
Compound of 不 (not) and 抜 (pull out, extract), literally 'cannot be pulled out', hence 'unshakable, firm'. The exact historical derivation is uncertain, but the meaning is transparent from the kanji.