"An Oxymoron is a combination of contradictory or incongruous words, such as 'Cruel Kindness' or 'Jumbo Shrimp' (Jumbo means 'large' while Shrimp means 'small'). It is a literary figure of speech in which opposite or contradictory words, terms, phrases or ideas are combined to create a rhetorical effect by paradoxical means."
Oxymorons.info - Oxymorons, Oxymoron