Jargon
Jargon is specialist language that is specific to an activity, hobby, profession, academic subject, or trade. In order for specialist language to be considered ‘jargon’ it needs to exclude people who don’t understand it.
Array Semantics
Litotes
Litotes is a language device where you combine a negative word (like “no”, “not”, “don’t”, “isn’t”, etc) with a word or phrase to express the opposite thing for effect. For example, “I’m not happy” means you’re unhappy.