THE CASSELL DICTIONARY OF SLANG. Edited by Jonathon Green. Cassell pound;25.

The constant and rapid evolution of street language can leave the uninitiated lost for words. So if you don’t know your rocket salad from your king dick, read on, as D J Taylor takes a butcher’s at two lexicons of slang

The worrying speed with which modern street language reinvents itself was brought home to me recently while I was reviewing Bret Easton Ellis’s latest novel, Glamorama. This labyrinthine satire of 1990s Manhattan tracks its quarry through a riot of up-to-the-minute neologisms, some of which I gamely decoded for the benefit of a presumably baffled readership.

In particular, I had a shot at a piece of dialogue in which Victor, Easton Ellis’s lumpen hero, says to his girlfriend: “You’re looking at me like I’m at a Hootie and the Blowfish concert.”

Make any sense to you? Well, Hootie and the Blowfish is a middle-of-the-road, meat-and-potatoes kind of US rock group. Victor, on the other hand, is as cool as a Lapland icebox. It seemed safe to assume the woman was annoyed with her paramour, and that this displeasure had something to do with a style misjudgment. Wrong, a correspondent flipped back. “Hootie and the Blowfish” was the latest gay slang for oral sex, having superceded the achingly passe “rocket salad”.

Ominously, neither the Oxford Dictionary of Slang nor its chunkier and more expensive rival from the house of Cassell have anything to say about Hootie and Co, or indeed rocket salad. The linguistic baton just gets handed on, you see, while the lexicographers puff helplessly in the rear.

Language is slippery enough at the best of times, but this kind of language - the closed-society jargon of the pizza parlour or the dealing room - simply slips off the etymological wallchart.

Many early Victorian novels, for example, contain the phrase: “I don’t half like him.” Nowadays, this means “I like him a great deal”, but in the 1830s it meant exactly what it says: “On a scale of zero to one I don’t like him as much as half.” Then, inexplicably, the usage began to change, settling down in the mid-century and leaving a trail of confusion in its wake.

No doubt Jonathon Green and John Ayto worried over how best to reproduce this kind of etymological development. The Oxford version, arranged by topic (“People and Society”, “Animals” and so on) gives a date for first use followed by an illustration, often many years apart. Green offers a straightforward alphabetical arrangement with occasional historical add-ons. But even this doesn’t quite do justice to terms such as “snob”, which originally meant a shoemaker, was then applied by Cambridge undergrads to townsfolk, and underwent another transformation in Thackeray’s The Snobs of England (a rather subtle definition along the lines of “one who judges by arbitrary criteria”) before attaining its indiscriminate modern usage of “upper-class condescender”.

Historical failings aside, both books are an invaluable testimony to the long-term slang preoccupations of sex (notably masturbation - scarcely a page of Green’s opus fails to yield up some variation on Mrs Palm and her five talented daughters), bodily functions (“talking to the big white phone” apparently means vomiting) and money. Larky bits of bygone inventiveness (“firkytoodle”, a 17th-century word for foreplay, or the cry of “No Tich!” that dissuaded Victorian diners from talking about the celebrated Tichborne claimant case) go hand in hand with bizarre geographical quirks. Depending on which hemisphere you inhabit, “king dick”, for example, seems to mean both a person in a position of power and “stupid, dull”.

Of the two, the Cassell dictionary is probably a shade more reliable. “Joey”, for instance, is marked down by Ayto simply as “a brass threepenny bit”. Any reader of George Orwell’s Keep The Aspidistra Flying, in which Gordon Comstock rages about a wretched silver joey sticking on the end of his finger, will have doubts about this, and sure enough Green tracks it back first to the fourpenny groat and then to the silver threepence introduced in the mid-19th century and sponsored by the radical MP Joseph “Joey” Hume.

Tracing the evolution of the “Joey” - transformed into a term of abuse by cab-drivers furious that the standard fare was quickly reduced to the value of the new coin - allows a sudden sharp glimpse into a particular kind of social history otherwise absent from the history books. Much slang - anarchic, invented on the hoof, essentially a kind of raspberry blown in the face of officialdom - opens a window into ordinary life that the average novel can only strain to reproduce.

That said, it will be difficult to look a rocket salad in the face again.

D J Taylor is a novelist and critic. He is writing a biography of Thackeray.