An oxymoron is a turn of phrase that contains a contradiction or paradox. Some familiar examples: definite maybe, same difference, poor little rich girl.

The word oxymoron derives from Greek: oxus means “sharp; quick,” and moros means “dull; foolish.” Sharply foolish? Eureka! Oxymoron is itself an oxymoron.

The plural is traditionally oxymora, but some now consider oxymorons acceptable also.

Oxymora have been around for centuries but have never gone out of date. Shakespeare’s plays and poems are teeming with them: “virtuous lie,” “tragical mirth,” “unpriz’d precious maid.” “I must be cruel only to be kind,” says Hamlet. “Parting is such sweet sorrow,” says Juliet to Romeo.

What are we to make of this line from Macbeth: “Fair is foul, and foul is fair”? Like any good oxymoron, this one jolts the reader. But when we consider that the words are spoken in tandem by three malevolent she-devils, the paradox makes sense.

Romantic poets like John Keats (“delicious diligent indolence”) and Lord Byron (“melancholy merriment”) were devising oxymora two centuries after Shakespeare. In the twentieth century, this durable figure of speech was embraced by a wide range of artists, from Ernest Hemingway (“young and lovely with the warm, scalding coolness”) to Andy Warhol (“I am a deeply superficial person”). And let’s not forget baseball’s Yogi Berra (“It gets late early out there”).

“The Sound of Silence,” a hit song of the sixties, employed oxymora in both its title and its lyrics: “People talking without speaking, / People hearing without listening.” More recently, the singer-songwriter Ne-Yo’s song “Beautiful Monster” became a No. 1 hit.

Movies have always used oxymora to grab our attention: Where East Is West, Urban Cowboy, Back to the Future, True Lies, Eyes Wide Shut, Slumdog Millionaire, The Little Giant (1933) and The Little Giants (1994), and at least three films titled Silent Scream. The late-sixties shocker Night of the Living Dead inspired the cable-TV megahit The Walking Dead, right down to the oxymoron in the title.

Countless oxymora have made their way into everyday speech: open secret, dry ice, benign neglect, wireless cable. The formal term for a piano, pianoforte, is an oxymoron—in Italian it means “soft loud.” And a sophomore is a “wise fool”—in Greek sophos means “wise,” and moros, as we’ve seen, means “foolish.”

The oxymoron has endured because it is so effective. We never seem to tire of this hardy rhetorical flourish. The mystery of the paradox commands our attention. We ponder the words and ask: How can fair be foul? How can a scream be silent? A great oxymoron underscores life’s ironies and reminds us that the things that matter are complicated.