The recent thread about the word 'Unresisted' got me wondering if there's an official term for when a word is turned into a negative by prefixing it with 'Un'. I know these definitely aren't words - unlike the debatable unresisted - but they're sometimes used for comic effect. I'm talking about things like 'unpregant', 'unstupid' - which are simply used to illustrate that whatever the word is saying, is not the case. They're not double negatives as such, but along those lines.
