天機不可泄露 [－机－－－－]

Jyutping tin1 gei1 bat1 ho2 sit3 lou6
Pinyin tiān jī bù kě xiè lù

Definitions (CC-CEDICT)
  1. lit. mysteries of heaven must not be revealed (idiom); must not be revealed
  2. I am not at liberty to inform you.