Litotes 

反语法

A special form of understatement is litotes, the assertion of an affirmative by negating its contrary: “He’s not the brightest man in the world” meaning “He is stupid.” The figure is frequent in Anglo-Saxon poetry where the effect is usually one of grim irony.

反语法是含蓄手法的一种特殊形式，以否定其反面来表示肯定，如用“他不是世界上最聪明的人”来意指“他愚蠢”。这一修辞手法常见于盎格鲁—撒克逊时期的诗歌，其效果往往是严酷的讽刺。