used in expressions that convey frustration and futility, such as 無奈|无奈[wu2 nai4] and 莫可奈何|莫可奈何[mo4 ke3 nai4 he2] (literary) / used for its phonetic value in writing foreign words
to compare / (followed by a noun and adjective) more {adj.} than {noun} / ratio / to gesture / (Taiwan pr. [bi4] in some compounds derived from Classical Chinese)