“神不知鬼不覺”，中文俗語，字面意思是“unknown to god or ghost”，形容事情做得很秘密，別人一點也不知道。可以翻譯爲“without anybody being aware of，not noticed by anyone”等。
例句：
他們設法神不知鬼不覺地離開了海岸。
They managed to get away from the coast undetected.
怎麼會有人神不知、鬼不覺地潛入皇宮呢？
How could anyone break into the palace undetected?