ㄧㄡˇyǒuㄊㄡˊtóuˊㄨㄟˇwěi

  1. 形容做事不能貫徹到底朱子語類··論語·公冶長》:聖賢中道不同畢竟做得完全學者有頭無尾不同。」·無名氏踏青·個人驀然驚覺有頭無尾。」虎頭蛇尾有始無終善始善終有頭有尾有始有終

to start but not finish (idiom)​; to fail to carry things through, lack of sticking power, short attention span