ˋㄅㄛˊㄕㄤˋㄓㄣˋchìbó‑shàngzhèn

赤膊上阵
  1. 膀子上陣打仗形容輕敵比喻掩飾貶義)​。 看樣子匪徒赤膊上陣警方」。

lit. to go into battle bare-breasted (idiom)​, fig. to go all out, to come out in the open