The word oxymoron is actually an oxymoron.

What do the following phrases have in common? – sweet agony, true myth, open secret, disgustingly delicious, deafening silence, pretty ugly, alone in a crowd, and virtual reality have in common? They are all oxymorons, aka figures of speech.

An oxymoron is used to call attention to an apparent contradiction. It is used to imply that an object can have two different qualities at the same time, making it a subject of study and analysis. Additionally, it is also used to add flavor to speech, as well as sound witty.
The word is derived from the 5th century Latin ‘oxymoron’, which is again derived from an Ancient Greek word meaning ‘sharp, keen’ and ‘dull, stupid’. In other words, the first portion of the word, ‘oxy’, means smart, and the second, ‘moron’, well, you know what it means.
This is what makes the term an oxymoron in itself. It is also used in sentences, not just in phrases. Examples: ‘I can resist anything, except temptation’, ‘Modern dancing is so old fashioned’, ‘No one goes to that restaurant anymore – It’s always too crowded’.