不顯山不露水 [－显－－－－]

Jyutping bat1 hin2 saan1 bat1 lou6 seoi2
Pinyin bù xiǎn shān bù lù shuǐ

Definitions (CC-CEDICT)
  1. lit. to not show the mountain and to not reveal the water (idiom); fig. to hide the key facts