An oxymoron (plurals: oxymorons and oxymora) is a figure of speech that juxtaposes concepts with opposite meanings within a word or in a phrase that is a self-contradiction. As a rhetorical device, an oxymoron illustrates a point to communicate and reveal a paradox. A general meaning of "contradiction in terms" is recorded by the 1902 edition of the Oxford English Dictionary.
The term oxymoron is first recorded as Latinized Greek oxymōrum, in Maurus Servius Honoratus (c. AD 400); it is derived from the Greek word ὀξύς "sharp, keen, pointed" and μωρός "dull, stupid, foolish"; as it were, "sharp-dull", "keenly stupid", or "pointedly foolish". The word oxymoron is autological, i.e., it is itself an example of an oxymoron. The Greek compound word ὀξύμωρον , which would correspond to the Latin formation, does not seem to appear in any known Ancient Greek works prior to the formation of the Latin term.
Oxymorons in the narrow sense are a rhetorical device used deliberately by the speaker and intended to be understood as such by the listener. In a more extended sense, the term "oxymoron" has also been applied to inadvertent or incidental contradictions, as in the case of "dead metaphors" ("barely clothed" or "terribly good"). Lederer (1990), in the spirit of "recreational linguistics", goes as far as to construct "logological oxymorons" such as reading the word nook composed of "no" and "ok" or the surname Noyes as composed of "no" plus "yes", or far-fetched punning such as "divorce court", "U.S. Army Intelligence" or "press release".
There are a number of single-word oxymorons built from "dependent morphemes" (i.e. no longer a productive compound in English, but loaned as a compound from a different language), as with pre-posterous (lit. "with the hinder part before", compare hysteron proteron, "upside-down", "head over heels", "ass-backwards" etc.) or sopho-more (an artificial Greek compound, lit. "wise-foolish").
The most common form of oxymoron involves an adjective–noun combination of two words, but they can also be devised in the meaning of sentences or phrases.