Definitions for "Litotes"
A diminution or softening of statement for the sake of avoiding censure or increasing the effect by contrast with the moderation shown in the form of expression; a form of understatement; as, " a citizen of no mean city," that is, of an illustrious city; or, "not bad", meaning "good".
a trope; deliberate understatement.
a figure of speech that emphasizes its subject by conscious understatement. An example from common speech is to say "Not bad" as a form of high praise.