Litotes - Λιτότητα

An affirmative meaning is expresses negatively. The opposite word is used with denial. With Litotis while something less is said, something more, or more significant, is implied.

Simply said rather than making a certain claim, we deny its opposite.

not many = few

I'm not ignorant of this = I know this

It is not a small thing = It is a great thing

no ordinary city." Acts 21:39 = an impressive city

That was no big deal = that was easy

That was not a surprise = I expected that

 Meiosis vs Auxesis