antiphrasis (noun)

1. The character is so 'smart' that he can't even tie his own shoe.

2. She wore a torn shirt and ripped jeans to the fancy dinner, the height of 'elegance'.

3. The movie's climax was when the hero 'accidentally' saved the villain from falling off the building.

4. The author beautifully described the dilapidated house as a 'mansion'.