"Oxymorons" are often characterized by:

♦ Oxymoron:
- A figure of speech in which apparently contradictory words are put together.
- When we use phrases like male-female, host-guest, civil war, an open secret, magic realism, or wise fool, we use oxymorons.

Example:
All changed, changed utterly:
A terrible beauty is born.
(Yeats: ''Easter 1916'')

Source: An ABC of English Literature - Dr M Mofizar Rahman.