adjectival nouns or quasi-adjectives (keiyodoshi)noun (common) (futsuumeishi) unbending;inflexible;tenacity;indomitableness

Futou

noun (common) (futsuumeishi)nouns which may take the genitive case particle 'no' no darse jamás por vencido;tener una voluntad de hierro;tener una voluntad inquebrantable

noun (common) (futsuumeishi)nouns which may take the genitive case particle 'no' yojijukugo tenacity;indomitableness;dauntlessness;inflexibility