钻牛角 (鑽牛角) zuānniújiǎo
          
              zuānniújiǎo 
              
              noun 
              honing a bull's horn; 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 
              Domain: Modern Chinese 现代汉语
              
                , Subdomain:  
              
              
                , Concept:  
              
              
              
                Notes: Same as idiom 钻牛角尖 (CC-CEDICT '鑽牛角')