Overstatement
Overstatement" basically means to exaggerate something, or say that something is greater than it actually is. It is using strong terms in order to stress a point.
Understatement
A figure of speech in which a writer or speaker deliberately makes a situation seem less important or serious than it is.
Hyperbole
Hyperbole: a literary device that is used to create emphasis. It is a
figure of speech in which
statements are exaggerated.
It may be used to evoke
strong feelings or to create a
strong impression, but is rarely
meant to be taken literally.