ㄨㄞˋㄍㄤㄋㄟˋㄖㄡˊwàigāng‑nèiróu

外刚内柔
  1. 外表剛強內心軟弱 紙老虎外剛內柔色厲內荏」。

soft on the inside despite one's hard shell, appearing tough on the outside as to mask one's inner vulnerability, also written 內柔外剛[nei4 rou2 wai4 gang1]