litotes

英 [laɪ'təʊtiːz] 美 [laɪ'totiz]

• n. 曲言法；间接肯定法；反叙法

1. from Greek litotes, literally "plainness, simplicity," from litos "smooth, plain, small, meager".
2. It is principally via double negatives. For example, rather than saying that something is attractive (or even very attractive), one might merely say it is "not unattractive".
3. Litotes is a form of understatement.