noun, noun which may take the genitive case particle 'no'
peerless in the country; unparalleled; matchless
A yojijukugo meaning that someone or something is without equal in the entire country. Often used in formal or literary contexts to praise exceptional talent or quality.
He was praised as a peerless master swordsman in the land.
This artwork is of unparalleled beauty in the country.
天下無双 also means 'unparalleled under heaven', but 天下無類 emphasizes being without equal in the entire country, while 天下無双 often implies being the only one of its kind.
無類 alone means 'matchless' or 'unparalleled', but 天下無類 adds the scope of 'in the country' or 'under heaven'.
A yojijukugo composed of 天下 (under heaven, the whole country) and 無類 (without equal, matchless). The exact historical origin is uncertain, but it follows a common pattern of four-character idioms expressing supreme excellence.