人不知，鬼不觉

MandarinEdit

simpl.		人不知，鬼不觉
trad.		人不知，鬼不覺

Literally: people don't know, and ghosts don't feel

Mandarin (Standard Chinese, Beijing)
Pinyin	`rén bù zhī, guǐ bù jué`
Zhuyin	ㄖㄣˊ ㄅㄨˋ ㄓ , ㄍㄨㄟˇ ㄅㄨˋ ㄐㄩㄝˊ
IPA ^(key)	/ʐən³⁵ pu⁵¹ ʈ͡ʂʐ̩⁵⁵ ku̯eɪ̯²¹⁴⁻²¹¹ pu⁵¹ t͡ɕɥ̯œ³⁵/

人不知，鬼不觉 (simplified, Pinyin rén bù zhī, guǐ bù jué, traditional 人不知，鬼不覺)

something that is so mysterious, that it cannot be known by humans or felt by ghosts