Oxymoron (noun)

1. A figure of speech that combines contradictory or incongruous terms.
2. A phrase or sentence that is self-contradicting, in which opposite or contradictory words are used together in a way that is surprisingly effective.

Origin:

Derived from the greek words "oxys" (sharp) and "moros" (foolish), oxymoron originally referred to a figure of speech in which contradictory or incongruous terms were combined.

Examples:

1. His promise to finish the work in less time was an oxymoron as he was always slow in completing tasks.
2. The "jumbo shrimp" is a classic example of an oxymoron.
3. The oxymoron of "military intelligence" is often used to describe the apparent contradiction between the two terms.
4. "Loud silence" is a fitting oxymoron to describe the stillness that surrounds a loud event.
5. "Organized chaos" is another well-known oxymoron.