龙头蛇尾 (龍頭蛇尾) lóng tóu shé wěi

lóng tóu shé wěi set phrase dragon head and snake tail; strong start but weak finish
Domain: Idiom 成语
Notes: (CC-CEDICT '龍頭蛇尾'; Guoyu '龍頭蛇尾'; Han Dian '龙头蛇尾')