赤膊上陣 [－－－阵]

Jyutping cek3 bok3 soeng5 zan6
Pinyin chì bó shàng zhèn

Definitions (CC-CEDICT)
  1. lit. to go into battle bare-breasted (idiom)
  2. fig. to go all out
  3. to come out in the open
Definitions (Wiktionary)
  1. phrase, figuratively, idiomatic
    to go all out; to go full speed ahead; to do something (often bad) without reservations or concealment
  2. phrase, idiomatic
    to go into battle barechested