The Hebrew verb arav (אָרַב) means to lie in wait, to set an ambush, or to lurk with intent to attack. It is used of military ambush tactics and metaphorically of the wicked who plot against the innocent.
Proverbs uses the ambush to describe the tactics of the wicked who lie in wait for blood (Proverbs 1:11). Peter's warning that the devil prowls like a roaring lion echoes this imagery. Spiritual vigilance is the antidote to ambush. Remarkably, at the cross what appeared to be Satan's greatest ambush became the decisive defeat of evil.