noun, noun which may take the genitive case particle 'no'
Emphasizes absolute uniqueness; there is no second. Often used in formal or emphatic contexts.
彼は唯一不二の存在だ。
He is a one-of-a-kind presence.
この作品は唯一不二の価値がある。
This work has unique value.
Synonymous yojijukugo with the same meaning; 唯一不二 is less common but equally emphatic.
A yojijukugo combining 唯一 (sole, only) and 不二 (no second), reinforcing the idea of absolute uniqueness.