“Litote” is also used in English {from the Greek litotes, meaning “plain” or “simple”} to refer to deliberate understatement {the opposite of hyperbole, really}. To quote fromA Glossary Of Literary Terms {5th Edition}, by M. H. Abrams, ‘A special form of understatement is litotes…which is the assertion of an affirmative by negating its contrary: “He’s not the brightest man in the world” meaning “He is stupid.”’
Or, as Tom Jones sings, “It’s not unusual…”