Shakespeare coined many of his own words, played around with others, used existing words in new and imaginative contexts, and joined pairs of words together to create compounds like watchdog (in The Tempest) and birthplace (in Coriolanus). He used rhetorical devices extensively, reworked the order of words in lines to fit rhythms and metres, and used puns and wordplay for humor, even making some of his characters deliberately misspeak or mispronounce their words purely for comic effect. As a result, his works provide the earliest citations of more than 9,000 different entries in the Oxford English Dictionary, while some estimates suggest that of the 31,534 different words he used, as many as 1 in 30 were of his own invention.

The problem with being so linguistically inventive, however, is that sometimes Shakespeare coined or used words in such a way that what he actually wanted them to mean remains unclear. In some cases this was undoubtedly his intention, and the fact some of his lines are deliberately ambiguous makes his plays all the more complex and intriguing. But in other instances, some of Shakespeare’s words are too vague or too perplexing to be easily understood, and have confounded actors, editors, directors, and students for years.

1. ARMGAUNT (Antony & Cleopatra, I.v)

In the opening act of Antony & Cleopatra, one of Cleopatra’s attendants, Alexas, describes a meeting with Marc Antony and talks of him mounting “an armgaunt steed, who neighed so high that what I would have spoke was beastly dumbed by him.” The second part of this line makes it clear that Antony’s horse neighed so loudly that anything he might have said would have been drowned out, but what about armgaunt? Some editors take this word literally, and suggest it literally means “gaunt-armed,” or slender-limbed. But if Alexas is trying to make Antony sound as gallant and heroic as possible, why would he point out how skinny his horse looks?

A more plausible suggestion is that Shakespeare’s “gaunt” is a play on gauntlet, the protective glove of a suit of armor, in which case the “armgaunt steed” might simply be an armored horse. Or maybe Shakespeare doesn’t want “gaunt” to mean skinny, but rather “not fat”—or, put another way, in good, healthy condition? Whatever Shakespeare actually intended is a mystery.

2. BALK'D (Henry IV: Part 1, I.i)

The aftermath of the Battle of Homildon Hill—a violent clash between the armies of England and Scotland in 1402—is recounted in the first act of Henry IV: Part 1, where the king proudly describes “ten thousand bold Scots, two-and-twenty knights, balk’d in their own blood” who have been left dead on the battlefield. But what exactly does Shakespeare mean by balk’d? Taken literally, a balk is a ridge or mound of land, or else one of the raised lines of earth left behind by a plow, so perhaps he means that the “two-and-twenty knights” have been left in heaps on the battlefield? As a verb however balk can also mean “to shun” or “to ignore intentionally,” which could mean that the fallen Scots have been left behind, unattended to and completely ignored. But some editors have claimed that balk’d could actually be a misspelling or misreading of baked, implying that the bodies have been left completely covered in dried blood.

3. BRAID (All’s Well That Ends Well, IV.ii)

In All’s Well That Ends Well, the pompous French count Bertram (who is already married to Helena) has been flirting with the young and innocent Diana, and after he leaves she disparagingly mutters to herself that “Frenchmen are so braid.” It’s a line that has puzzled editors for years, not least because no one known exactly what Shakespeare meant by braid. Samuel Johnson suggested that the word “seems to signify deceitful,” in which case it might be related to the old Scots word braidie, meaning “crafty” or “cunning.” But maybe Diana is implying that Frenchmen are twisted or tight, like braided hair? Or maybe she means braid in the sense of a decorative trim or brocade, implying that Bertram is all show and no substance?

4. COCK-A-HOOP (Romeo & Juliet, I.v)

In Tudor English, to set the cock on the hoop meant to force the spigot (i.e. the cock) of a barrel of ale (i.e. the hoop) fully open—or else to remove it entirely—so that an uninterrupted flow of liquor gushes out. It's from here that we took the expression cock-a-hoop, meaning “excited” or “overjoyed,” but Shakespeare’s use of cock-a-hoop in Romeo & Juliet doesn’t seem to match either meaning. He used it in an angry exchange between Lord Capulet (Juliet’s father) and Tybalt (her cousin) after Tybalt discovers that Romeo, a Montague, has shown up at a party at Lord Capulet’s home. Tybalt declares his intention to fight Romeo, but Lord Capulet furiously knocks him back: “Am I the master here or you? Go to! You’ll not endure him! … You’ll make a mutiny among my guests! You will set cock-a-hoop!”

Judging by the context, Lord Capulet doesn’t seem too concerned that Tybalt will suddenly begin drinking recklessly, but rather that he will cause chaos at the party. Ultimately different editors have suggested that Shakespeare wanted “to set cock-a-hoop” to mean something like “to bring a gathering to a premature end,” “to act wildly” or “with no social restraint,” or else “to act selfishly,” and “enjoy oneself without any regard to anyone else."

5. DEMURING (Antony & Cleopatra, IV.xv)

Shakespeare was the undisputed master of verbing, the semantic process by which words like nouns and adjectives are reused as if they were verbs. According to some editors, he did precisely that in Act 4 of Antony & Cleopatra, when Cleopatra talks of Marc Antony’s wife Octavia “demurring upon” her “with her modest eyes.” If this is true, then the root of Shakespeare’s demuring is the adjective demure, in which case Cleopatra really means that Octavia will “look demurely”—or “with affected modesty,” as Samuel Johnson explained—at her, in a patronizing attempt to keep her happy. But other editors claim that Shakespeare is simply using (albeit with a misspelling) the existing verb demur, which in Elizabethan England could be used to mean “to be hesitant,” or “to remain unsure of something.” If this is the case, then Cleopatra might instead be implying that Octavia will look at her with a doubtful, suspicious gaze.

6. EFTEST (Much Ado About Nothing, IV.ii)

“Yea, marry, that’s the eftest way.” So says the slow-witted and pompous constable Dogberry in Much Ado About Nothing. Dogberry is well known for his blundering malapropism-filled language, but the problem with eftest is that the word he’s muddling up isn’t entirely clear from the context. Various explanations suggest that he really means something like “quickest,” “neatest,” “most convenient,” or “readiest,” but whatever Shakespeare really intended remains unclear.

7. GLASSY (Measure for Measure, II.ii)

In Measure for Measure, Claudio, the brother of the play’s lead character Isabella, is sentenced to death on the hateful Lord Angelo’s command. In Act 2, Isabella meets with Angelo and pleads for him to let her brother go, and in a lengthy and dramatic scene, the pair discuss the many foibles and imperfections of men. “Could great men thunder as Jove himself does,” Isabella explains, “Jove would ne’er be quiet.” Mankind’s “glassy essence,” she goes on, “…plays such fantastic tricks before high heaven as make the angels weep.” Essence here means “character” or “disposition,” but quite what Shakespeare means by calling it “glassy” is unclear. Perhaps he means “brittle” or “breakable,” like glass? Or perhaps he means “reflective” or “mimicking,” like a mirror? Or perhaps he means “transparent,” in the sense of men being unable to hide their true feelings?

8. IMPETICOS (Twelfth Night, II.iii)

The Oxford English Dictionary calls impeticos “a burlesque word put into the mouth of a fool,” and they’re quite right. It’s used by Feste, the sharp-witted clown in Shakespeare’s Twelfth Night, who happens to mention at one point that he “did impeticos thy gratillity.” Gratillity is apparently a deliberate mispronunciation of “gratuity,” but it’s what Feste has done with his gratuity that is unclear. Impeticos could be a mispronunciation of impocket, a Shakespearean invention implying that Feste has simply pocketed the cash. Alternatively, Samuel Johnson's suggested that the word should actually be impetticoat, in which case Shakespeare might be referring to the long colourful robes that clowns like Feste would often dress in. Or else impetticoat might imply that he spent it on an unnamed woman (or women).

9. PORTAGE (Pericles, III.i)

Act 3 of Pericles begins with the eponymous prince on board a ship in the middle of a great tempest, while below decks his wife Thaisa is giving birth to their baby daughter, Marina. Thaisa dies in childbirth and her nurse, Lychordia, brings the baby up on deck to deliver the news to Pericles. Holding Marina in his arms, Pericles exclaims, “Poor inch of nature! Even at the first, thy loss is more than can thy portage quit, with all thou canst find here.” A portage is literally the quantity of space or weight that a sailor was permitted on board a ship in which to transport his own cargo, which he can then sell or trade for his own personal gain.

Perhaps Shakespeare is here implying that Thaisa’s death is too great a loss for Marina ever to compensate for? Or maybe he’s talking about the literal portage of the ship—whatever its value might be, Thaisa’s death is too costly a loss? Or maybe he simply means “the arrival at a port,” a metaphorical image of the start of Marina’s life? Or maybe, as some editors have suggested, the word is so troublesome that it must in fact be a misprint of parture, an old fashioned word for childbirth?

10. WATCH-CASE (Henry IV: Part 2, III.i)

A watch-case is a case for a watch, yes? Well, not in Shakespeare. He used the word in a long monologue in Henry IV: Part 2, in which the restless, insomniac king talks aloud to Sleep itself. “O thou dull god, why liest thou with the vile [common people] in loathsome beds, and leavest the kingly couch a watch-case or a common ’larum bell?” The king is complaining that Sleep allows lowly people to rest easily, whereas the king’s bedroom is as noisy as a belltower (a “’larum bell”). So we know from the context that Shakespeare is using “watch-case” to mean “somewhere where there is constant noise,” but does he really mean the case of a pocketwatch? Or does he just mean the part of your arm where you wear a watch, or the place where you put a watch at night? Or does he mean “watch” as in “guard-post,” where there would be a constant military presence, and a constant change of sentry throughout the night? No one knows for sure.