A hyperbole is an exaggeration.
In Act 4, Scene 1 of Shakespeare's "Macbeth," the first apparition tells Macbeth to beware of Macduff, but the second says he does not have to kill him if he has no reason to fear him. Nevertheless, Macbeth resolves to seize the town of Fife, raid Macduff's castle and murder him as well as his wife, children and everyone in line of succession. As a result, Macbeth expects that will help him conquer his fear and sleep easily at night.
