DICT.TW Dictionary Taiwan

 鑽牛角尖 [ㄗㄨㄢ ㄋㄧㄡˊ ㄐㄧㄠˇ ㄐㄧㄢ; zuan1 niu2 jiao3 jian1]
 lit. to penetrate into a bull's horn (idiom); fig. to waste time on an insoluble or insignificant problem
 to bash one's head against a brick wall
 a wild goose chase
 a blind alley
 to split hairs
 ◄ ►