"Antres" is among the rarest of rare words. Shakespeare's Othello speaks of "antres vast and deserts idle" in that magnificent oration in which he takes issue with the the Venetian bigotry that he was only able to win white Desdemona by employing drugs and witchcraft." No, it wasn't because he was a sorcerer; it was because he was heroic and accomplished. "Antres" is one of the exotic words that defines the great African general as a non-Venetian -- an outlander, an "erring barbarian," an "extravagant and wheeling stranger."
Shakespeare coined "antres" just for the occasion, deriving it from Latin antrum, a cave. He never used "antres" again, nor did anyone else until Keats fleetingly revived the word two centuries afterward. "Antres" never domesticated into English and remains curious and remote, eternally in need of the explanatory footnote. It is unlikely that Shakespeare expected that a popular or even a courtly audience would grasp "antres" at first hearing. It's a risky word, but Shakespeare didn't become Shakespeare without taking risks.
The playwright coupled the neologism "antres" to another shiny new Latinism to produce "antres vast," a phrase which translates into the language of 2010 as "really big caves." Yet no translation can do justice to the spacious resonance of "antres vast." These are monstrously huge caverns -- grown grander and even more inaccessible because Shakespeare opportunely placed the modifier after rather than before the noun. "Antres vast" are a hundredfold more mysterious -- darker, more echoic, more glinty with stalactites and stalagmites -- than "vast antres."
"Antres vast" occurs in tandem with a second and equally remarkable noun-adjective combination: "deserts idle." Othello reports that before he came to Venice, he had not only traversed "rough quarries, rocks, and hills whose heads touch heaven" but had also dwelt among "antres vast and deserts idle." Strictly speaking, deserts cannot be "idle," but they can be vacant or useless. "Deserts idle" reinforces and augments "antres vast." Taken together, the two phrases are infinitely more evocative than either alone.
As a structure of sound, "antres vast and deserts idle" pivots on the "d" of "and" and the "d" of "deserts" and it positions "antres" and "idle" in symmetrical opposition. The two key words are dissimilar yet ingeniously interlinked, each comprised of an open vowel (Antres, Idle), a dental (anTres, iDle), and a liquid (antRes, idLe). It is not by accident that "antres vast and deserts idle" is such a euphonious and mouth-filling phrase.
Shakespeare not only invented "antres" for Othello's oration but also took care to surround it with other linguistic novelties. For example: Othello claims to have encountered "cannibals that each other eat/ The anthropophagi." "Cannibal" is now a commonplace noun, but in 1604 it was a newcomer to the language. "Cannibal" derives from "Carib," the name of a recently-encountered people--reputed to be man-eaters --who gave their appelation to the sea in which they lived. "Cannibal" was sufficiently strange--it had only made harbor in England (arriving by way of Spain) in the 1550s--that Shakespeare felt a need to define it, which he did once in English ("that each other eat") and once in Greek ("anthropophagi"). "Anthropophagi," a word that had originated with Herodotus, was as new to English--and as seldom employed--as "cannibal."
"Antres vast," "deserts idle," "cannibals" and "anthropophagi" play crucial parts in Othello's stirring autobiographical fragment.
I spake of most disastrous chances,
Of moving accidents by flood and field,
Of hair-breadth scapes i'th'imminent deadly breach,
Of being taken by the insolent foe
And sold to slavery; of my redemption thence,
And portance in my travel's history:
Wherein of antres vast and deserts idle,
Rough quarries, rocks, and hills whose heads touch heaven,
It was my hint to speak -- such was the process.
And of the cannibals that each other eat,
The anthropophagi, and men whose heads
Do grow beneath their shoulders.
It's an astonishing story, each element more incredible than the one that precedes it. Hair-breadth escapes? Every hero can boast of them. Redemption from slavery? A bit less likely. Hills whose heads touch heaven? A forgiveable hyperbole. Cannibals? Surely, less believable still. The Othello landscape then crosses the border from exotic to fabulous when it adduces "men whose heads/ Do grow beneath their shoulders." The headless men are the blemmyae --Nubian or ometimes Ethiopian-- who were a feature of pseudo-anthropological folklore from Pliny to Sir Walter Raleigh. The skepticism that these monstrous creatures ought to provoke is diluted because the road to the blemmyes passes through "antres vast and deserts idle." If audiences had not been lulled and seduced by "antres," they might dismiss Othello as a mere braggart soldier--rather than admire him for the near-magician that he becomes in his self-dramatization.
Shakespeare had yet another purpose for "antres vast." In the sentence that treads on the heels of the "men whose heads/ Do grow beneath their shoulders," Othello abruptly turned his attention to Desdemona. His language dulls. "This (i.e. his exotic narrative) to hear would Desdemona seriously incline,/ But still the house affairs would draw her hence." Shakespeare strategically contrasts Othello's vocabulary to Desdemona's when he juxtaposes "antres vast" to "house affairs." Only the tinnest of ears can fail to be struck by the difference between the two phrases. Antres vast--house affairs; house affairs--antres vast. The gap between these two most pregnant phrases is small enough to allow the electric impulses of sex and romance to spark, but is too wide to allow genuine understanding or empathy to shoot the gap. The tragedy of Desdemona and Othello arises out of the unbridgeable space between "antres vast" and "house affairs."
Shakespeare therefore knew exactly what he was about when he invented the word "antres." If he had been in a more antic mood, less determined to characterize Othello's massive dignity, he might have coined a word from another Latin word for cave, e.g. spelunca. But "spelunkies vast" -- or even "spelunkies splendid" -- could not possibly do the work of "antres vast."