有頭威，冇頭陣 [－头－－－头阵]

Jyutping jau5 tau4 wai1, mou5 tau4 zan6
Pinyin yǒu tou wēi1 mǎo tóu zhèn

Definitions (CC-CANTO)
  1. to have a start strong but a weak finish [colloquial]