Arizona Gov. Jan Brewer “has the cojones that our president does not have,” Sarah Palin rabble-roused on Sunday. Anatomically, the one-time vice-presidential candidate has it all wrong: The president has cojones, the Spanish word for balls, while the female Brewer does not. Of course, cojones also means bravery, and she was surely relying on this figurative sense to imply that Obama lacks courage. How did a Spanish slang word sneak into the American vernacular?

Ernest Hemingway. The first English-language text to contain the word cojones as a metaphor for bravery is Hemingway’s 1932 book on bullfighting, Death in the Afternoon. “It takes more cojones,” he wrote, “to be a sportsman where death is a closer party to the game.” Subsequent examples cataloged in the Oxford English Dictionary use cojones more literally, as in this colorful line from Noel Behn’s 1966 novel The Kremlin Letter: ” ‘Hit that big cow in the crotch! … in the cojones,’ he roared at her, pointing to his own.” Naturally, books can only affect a language so much. Widespread familiarity with both senses of cojones is probably the result of contact with Spanish-speaking immigrants and was likely current in cities with large Hispanic populations (such as San Antonio, Los Angeles, and El Paso) before the rest of the country.

The linguistic association between testicles and valor goes deeper than cojones. The Galician collóns, the French couilles, and the Italian coglioni all refer to both the male generative gland and the more abstract quality of gumption. In English, balls has meant testicles since at least the 14th century, but there’s no textual evidence of writers using balls to denote courage until 1903, when William Ernest Henley wrote of Robert Louis Stevenson “All eloquence and balls and brains; Heroic and also infantile.” More directly, the “lover” in D.H. Lawrence’s 1928 Lady Chatterley’s Lovercomplains, “You say a man’s got no brain, when he’s a fool. … And when he’s got none of that spunky wild bit of a man in him, you say he’s got no balls.”

There’s also a long tradition of literally believing bravery comes from the balls. The 16th-century anatomist John Banister, for instance, argued that testicles are “the cause of strength and manhode.” His younger contemporary, Helkiah Crooke, felt much the same: “Surely the power and virtue of the Testicles is very great & incredible, not onely to make the body fruitfull, but also in the alteration of the temperament, the habit, the proper substance of the body.” (Habit here means bodily condition as well as disposition and character.)

The ancient Greeks, for their part, related courage to masculinity, and their most common word for courage was andreia, which comes from the noun anēr or man. The battlefield invocation to “be men” (aneres este) appears 10 times in The Iliad. A Classicist also assured the Explainer that both the Greeks and Romans made the direct connection between testicles and courage, though it’s not easy to find instances of straight verbal abuse (“strap on a pair”). What we do have are Attic comedies in which large testicles are a sign of potency in the literal and figurative senses of the word and the absence of testicles signifies the opposite. As it happens, there’s also a contradictory strain in Classical art associating heroic virtue (including courage) with small testicles, which implied self-control. Vase paintings and sculptures sometimes depict mythological male heroes with small testicles and comic figures with grotesquely exaggerated members.

Sarah Palin was not the first American political figure to swing around cojones. In the mid-1990s, a Cuban jet fighter pilot bragged that he’d shot a civilian plane in the cojones. Then-ambassador to the United Nations Madeleine Albright countered, “Frankly, this is not cojones; this is cowardice.”

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Explainer thanks Emily Greenwood of Yale University, Timothy Jay of the Massachusetts College of Liberal Arts, and Ralph Rosen of the University of Pennsylvania.

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