a figure of speech by which a locution produces an incongruous, seemingly self-contradictory effect, as in “cruel kindness” or “to make haste slowly.”
Origin: 1650–60; < Late Latin oxymorum < presumed Greek *oxýmōron, neuter of *oxýmōros sharp-dull, equivalent to oxý(s) sharp (see oxy-1) + mōrós dull (see moron)