To waylay and to ambush are to attack suddenly from a place of hiding. Waylay is generally used when a person is set upon by robbers, assassins, etc., who have been lying in wait for him: armed bandits waylaying travellers in a deserted stretch of the valley. Ambush suggests that the object of attack is a military enemy: In the Maori Wars, British soldiers were frequently ambushed .

In the context of this discussion, surprise means to attack an enemy without warning ?often, but not necessarily, from a place of hiding: The main body of the army crossed the river under cover of darkness, in order to surprise the enemy at dawn.