Like poetry and pornography, slang is easier to recognize than to define. Most of it is disapproved of by someone, but obscenity alone doesn’t qualify. It isn’t slang, for example, to refer to manure with a four-letter word. But if you put the article “the” in front of that four-letter word and equate the president-elect of the United States to it, then slang it is, and very complimentary. Further complicating matters, a great deal of slang is completely inoffensive. Journalists call the first sentence of an article the lede, the last the kicker, the motive for reading it the hook and the paragraph that encapsulates its argument the nut graf–terms that might puzzle an outsider but won’t scandalize anyone.

One comes a little closer to a definition of slang by thinking about context. Dirty words suggest that the audience is no better than the speaker, and vice versa. Slang, on the other hand, usually suggests that speaker and audience share membership in a group. A prostitute who describes a slow-to-satisfaction customer as a thirty-three, thereby analogizing him to the standard speed for long-playing vinyl records, is probably not speaking to a police officer. A gay man who describes a lover with a similar quirk as long-winded is probably not speaking to a heterosexual. The implied identifications are flexible, however. If a gay hairdresser in London offers to zhoosh you, it’s safe to accept his titivation even if you’re a straight man. The word might make you blush, but it won’t compromise your orientation; it merely dignifies you with honorary membership in the group of people who understand how he talks.

Sometimes a slang word or phrase springs free of the people who coined it, but it remains slang only for as long as it trails groupiness of some kind, however attenuated or abstract. You needn’t work for the sanitation department to call maggots disco rice, a term recorded by the New York Times in July 2004, but the term nonetheless implies that a vivid acquaintance with the larvae was picked up somewhere. In September, when a writer for New York magazine hailed Sarah Palin’s promised son-in-law for attracting “the cougar vote,” the writer probably didn’t intend to signal that he and his readers belonged to the romantic community that unites older women and younger men. But he probably did expect that he and his readers shared an urbane taste for following pop-culture reportage on sexual behavior into its sillier vicissitudes.

To a lexicographer, slang’s abundance may present an even greater challenge than its definition. Although humans coin words as prolifically as bees make honey, dictionaries of standard English only include lexemes that have become a stable currency among strangers. Slang is not confined by this useful limit. My boyfriend and I refer to going online as checking our bids, in memory of a bygone fascination with eBay. Because we once elaborated the no-chicken label on a box of vegetarian broth into a fowl-friendly warning–“No, no, chicken! Keep away from the boiling water!”–we now always call the broth no-no chicken. The glossy young rich who crowd us out of our favorite restaurants are known to us as kittenheads, on account of a bus-side ad I once saw that juxtaposed an enormous fluffy white feline head, a crystal goblet full of glistening diced organ meats and the slogan “Next Stop, Uptown.” This is just the tip of the iceberg of our private slang, and we’re only two people. Multiply our sample by all the groups, large and small, who improvise with the English language for their own convenience and pleasure, and you see the problem. Slang is virtually infinite. It helps to exclude slang that hasn’t been published, but in the Internet age it doesn’t help much.

To steer successfully between the normal and the too-peculiar, a slang dictionary must be an exercise in tact as well as linguistics. As a result, it’s likely to evince personality. Stone the Crows, the second edition of Oxford University Press’s dictionary of modern slang, is eccentric and risqué, like a well-read, intermittently potty-mouthed uncle. The charms of The Routledge Dictionary of Modern American Slang and Unconventional English, on the other hand, are somewhat coarser, and bring to mind a younger brother with troubled friends who has memorized long stretches of dialogue from movies starring stoners or mobsters. To explain the word “fairy,” the Oxford quotes Evelyn Waugh. To explain “dirtbag,” the Routledge quotes Ferris Bueller’s Day Off. It isn’t quite fair to compare the two, because the Oxford collects English-language slang in use anywhere (but predominantly in Britain) since World War I and the Routledge restricts itself to America since World War II. Accordingly, the Oxford features “Joe Bloggs” (an average fellow) and “Joe Soap” (a gull), while the Routledge has “Joe Sixpack” (a blue-collar type), “Joe Schmo” (a representative dimwit) and “Joe Cool” (someone who aspires to the sang-froid of Snoopy in sunglasses). But the difference in catchment areas cannot alone explain how little overlap there is. The Oxford claims that the Swiss itch, a style of tequila drinking that involves licking salt beforehand and sucking lime afterward, is American and dates from 1959, but the Routledge doesn’t know about it. The words “love apple,” “ladies’ aid” and “joybox” look naughty but have innocent meanings, a contrast that might be expected to appeal to the Oxford’s whimsical spirit; but only the Routledge reveals that they refer to a tomato, a pool-cue support and a piano, respectively.

And that’s as it should be. There’s more slang in the world than dictionaries can capture, and there’s no reason for them to repeat one another’s labor. Absent from both the Oxford and the Routledge, for example, are “lede,” “hook” in its journalistic sense (unless you count the seventeenth meaning given by Routledge: “in a confidence swindle, the stage in the swindle when the victim is fully committed to the scheme”), “nut graf,” “disco rice,” “cougar” and “kittenhead.” (I ought to confess, though, that the Oxford taught me “zhoosh,” and the Routledge “thirty-three” and “long-winded.”) It is easy and uncharitable to prolong such a list, but I’m unable to resist adding that neither dictionary mentions “beemo,” the mildly pejorative word for a zealous student that haunted my 1970s childhood in central Massachusetts; “gaybait,” a generalized taunt from the same milieu, whose literal meaning occurred to none of us there, I’m fairly sure; “demap,” a synonym for kill coined by David Foster Wallace in Infinite Jest; “muzzleloader,” gay slang for someone who shares what is said to have been Alfred Kinsey’s chief sexual perversion and which means what you think it means; “sketchy,” an adjective that I overheard on the subway just last night in reference to a potentially dangerous situation; or “money quote,” a piece of blogger’s cant patterned after a term of art in the porn industry and used to introduce a crucial excerpt–the nut graf as seen from the other side of the table. Both dictionaries dip into Internet slang–the Routledge knows what it means for a McCain adviser to complain that Sarah Palin didn’t have the “bandwidth” to prepare for her media interviews, and the Oxford is down with “warez” as a synonym for pirated software or media–but neither mentions the new Internet-accelerated interjections “meh” (“I am unimpressed”) or “teh” (“I am emphasizing and ironizing simultaneously by deliberately mistyping the word ‘the,'” often used in conjunction with the spurious plural “Internets,” which was pioneered by George W. Bush during the 2004 presidential debates).

Yet these dictionaries contain riches. As one sifts them, one may even be led to imagine that they reveal our deepest preoccupations. People used to spend themselves in sexual climax; later they came, and I’ve long wondered what shifted the metaphorics underlying the highest human pleasure from commerce to presence. Nowadays people merely cum, as if the very spelling of the word rebelled against anything so grand as immanence and insisted that the act was no more than physiological. As research for further such speculations, I tried for a while to keep score while reading the Routledge–toting up the dingle-dangles, meat whistles, one-eyes and jing-jangs to see whether they outnumbered or were outnumbered by the maw-maws, chi-chis, dubbies and jigglies–but in the end I despaired. My psychoanalysis is therefore no more than impressionistic.

It nonetheless seems to me that the American id, viewed through the lens of slang, dwells much on human worthlessness, failure, drug addiction, homosexuality (imagined as a come-down, not a turn-on), oral sex, penises and breasts–as if the nation collectively feared that it might be sucking hind tit (suffering deprivation on account of low status) and were in search of compensation. At the end of Stone the Crows there’s a very clever subject index where one may see at a glance all the slang for, say, a drinking spree: “on a whizzer; on the bash; on the batter; on the bend; on the piss; on the skite.” The collective id of the Commonwealth nations is therefore easier to assess, and my sense is that it highly values intoxication, foolishness, money and cheating. Perhaps these are more complex vices than the American ones, or perhaps the slang of one’s own people inevitably becomes monotonous. In any case, I found myself tiring of deep-dicking American macks and the deprecation of knobslobbers, pratt boys and morphodites. But those kiwis and limeys! Those gumsuckers, bananalanders and their corresponding sheilas! They track with one another instead of merely dating, put anchovies on toast and call them whales, shout one another drinks, get squiffy together, go home for a little rumpty-pumpty and complain the next morning that they must have been starkers. It’s irresistible, as are the Oxford’s usage examples. This 1945 quote from Lawrence Durrell, for instance, illustrates a word for an angry letter: “I was afraid…that you would write me a stinker calling me a peach fed sod.” (The peaches are not explained.) I even found strangely compelling this 1970 line from the Daily Telegraph that instanced a synonym for addiction: “Hundreds of domestic pets die each year after becoming ‘hooked’ on slug bait.” One almost wants to try some.

The Oxford’s etymologies are also entertaining. The affectionate moniker “toots,” for example, ultimately derives from “foot,” and the Australian put-down “warb” (“an idle, unkempt, or disreputable person”), from the maggot of the warble fly. The Routledge, for its part, excels in its explanatory notes, which give a word’s originating or most famous-making context. The entry for “tea-room,” for example, follows gay restroom sex from the late nineteenth century through Laud Humphreys’s acclaimed 1970 sociological study to the recent travails of Idaho Senator Larry Craig. A note for “gonzo” credits its coining to a friend of Hunter S. Thompson’s, and one for “hillbilly heroin” refers to the oxycodone addiction of radio personality Rush Limbaugh. It transpires that “pixie” became celebrated after a reference to the amours of Roy Cohn during the McCarthy hearings.

One of the most amiable kinds of slang is the micro-joke, as in “deep sea fishing” (medical slang for exploratory surgery) or “dorm rot” (college slang for a hickey). The Routledge reports that a gay man who flits from one doomed romance to another is known as a Camille and that ordering Navy recruits to tread water at length is called drown-proofing them. But I think my favorite slang genre, which I hadn’t previously realized was populous enough to constitute one, consists of phrases derived from the names of pop-culture figures, remembered and unremembered. The Routledge contributes a few American examples: to pull a Hank Snow is to leave, in allusion to Snow’s chart-topping 1950 country song “I’m Movin’ On,” and a John Wayne is an exaggerated punch. But the British and the Australians are fonder of them, so many more are to be found in the Oxford. A Jimmy Woodser is a drink one drinks alone, named for the Australian poem “Jimmy Wood,” about a “solitary Briton” who, according to teh Internets, denounced “shouting” and preferred to “drink his poison–solus–nice and quiet.” In drinking or any other endeavor, solitude may be described as being on one’s tod, because the last name of the jockey Tod Sloan rhymes with “alone.” Indeed, rhymes motivate quite a few. A Captain Cook is a look, a Harry Tate is a nervous state and Britney Spears are beers. More ingeniously, Harriet Lane is canned meat, in memory of a famous murder victim, and Fanny Adams is meat stew for a similar reason. A Kathleen Mavourneen is an interminable prison sentence, evoking the refrain of a song with that title: “It may be for years, it may be for ever.” The V-for-victory gesture that Americans associate with Nixon is in Britain called a Harvey Smith, because there a horseman by that name popularized it. “Gordon Bennett” expresses astonishment by its resemblance to “God blind me” and in honor of the scurrilous nineteenth-century newspaper editor James Gordon Bennett, who no doubt deserves to be remembered in his afterlife as an expletive. And if you suspect me of having sucked this review out of my thumb, as a South African friend of mine used to put it, feel free to dismiss it as all my eye and Betty Martin. No idea who she is, but apparently she’s been around since the 1780s.