ㄇㄠˊmáoㄙㄜˋㄉㄨㄣˋdùnㄎㄞkāi

  1. 比喻馬上開悟忽然明白西遊記·》:無力三公茅塞頓開。」金瓶梅·》:當時一席話西門心地透澈茅塞頓開。」

murky darkness suddenly opens (idiom)​; a sudden flash of insight and all is clear