Oxymoron

An oxymoron is a phrase. Parts of such a phrase seem to be contradictory or incongruous. Such a situation arises because of ommition of certain word or words in the phrase or addition of certain word or words in that phrase.

'Pretty bad', 'Vegetarian meatball' etc can be cites as examples of oxymoron because one or the other word seems to be contradictory when compared to the other.