神出鬼没,汉语成语,像神鬼那样出没无常。原指用兵灵活机动,今多比喻行动变化飞速,出没无常,不可捉摸。可以翻译为come and go like a shadow,appear and disappear mysteriously等。
例句:
游击队神出鬼没,搞得敌人晕头转向。
The guerrillas came and went mysteriously, driving the enemy out of their wits1.
他神出鬼没,不知一天都在做什么。
He is a mysterious person; no one really knows what he is doing from day to day.