The language of the day was becoming ever more complex: thanks to new discoveries in science and geography, and to the ever multiplying energies of writers, vocabulary choices were increasing almost by the day. To use English properly was, in a word, daunting. Opportunities for making oneself look and sound foolish were everywhere. Hence the need for the balm of Piozzi's enormous book. She would show one how to sound one's best.
The way she tried to accomplish this, mind you, ruffled some feathers. It was unimportant to her if what one said was lexically imperfect—that was just a matter of pedantry. Style and the veneer of sophistication were all. "Synonymy," she reassured her readers, with a remark that would have infuriated Roget, "has more to do with elegance than truth."
The organization of Piozzi's book is peculiar compared with that of modern synonymies. She grouped what she regarded as synonymous words together and then explained in a longish paragraph the nuances that distinguished them. Take, for example (as quoted in Emblen's book),
AFFABILITY, CONDESCENSION, COURTESY, GRACIOUSNESS
Are nearly synonymous, though common discourse certainly admits that an equal may be affable, which I should still think wrong in a printed book, and unpleasing everywhere, because the word itself seems to imply superiority. We will allow however that the lofty courtesy of a princess loses little of its graciousness, although some condescension be left visible through the exterior affability; but that, among people where talents or fortune only make the difference, a strain of polished familiarity, or familiar politeness (call it as you will) is the behaviour most likely to attract affectionate esteem.
In Piozzi's view, a slight but important difference of class association existed in the employment of these four words. The manner in which each was used—except among those whose "talents or fortune" rather than rank distinguished them—depended on who was being affable or courteous to whom: a duke might be affable to a commoner; it behooved a commoner to be courteous in return, and most decidedly not affable.
Other synonymies were published between Piozzi's and Roget's—the biggest and most durable being George Crabb's work of 1816, English Synonymes Explained, in Alphabetical Order; With Copious Illustrations and Explanations Drawn From the Best Writers. It was a cumbersome book, widely criticized for being prolix in style and maddeningly circular in argument. But it, too, answered a seemingly urgent need: sixteen editions were printed over the thirty-six years before Roget swept the board.
Crabb's success spawned other synonymies: in the decade before Roget fourteen synonym finders were published, known today to the small fraternity of thesaurus collectors by the names of their compilers—among them William Carpenter (1842), George Graham (1846), James Jermyn (1848), and James Rawson (1850). Many such books could have helped users to jog their memories. It is rather charming to suppose that such a book, slipped furtively from a partygoer's pocket, might act as a sort of hip flask for the conversationally parched. The image may strike us as more than a little awkward, but perhaps the etiquette of the time made the use of such a little book no trickier than the use of a phrase book when abroad.
But although all these volumes listed hundreds upon hundreds of almost interchangeable words and phrases, and gave helpful hints as to how each might be suitably employed, none of them—with the possible exception of Piozzi's—took care to examine the subtle notion of the synonym itself. None of the editors wondered—at least not in print—why a language as complex and finely tuned as English would include any two words that meant exactly the same thing. Was there such a thing as a real synonym? Or had every word been created for a unique purpose? Roget, who began as early as 1805 to consider the need for some formal classification of the chaotic entity that was then the English language, was fascinated by these questions. The answers he constructed led him, fifty years later, to the creation of this organizational masterpiece that bears his name.
Consider some of the words that are listed in the OED (under synonym) as examples of as-near-as-it-comes synonymy. The first are serpent and snake. Are these words true synonyms? In terms of pure definition, yes—sort of. Serpent is defined in the OED as "any of the scaly limbless reptiles regarded as having the properties of hissing and 'stinging'; Zool. a reptile of the group Ophidia; a snake." Snake is defined as "one or other of the limbless vertebrates constituting the reptilian order Ophidia (characterized by a greatly elongated body, tapering tail, and smooth scaly integument), some species of which are noted for their venomous properties; an ophidian; a serpent." The difference at this level is minuscule: one definition is more comprehensive, mentioning the vertebrated skeleton and the scaly integument; the other is somewhat more colorful, accentuating the hissing noise that the beast is able to emit.
Were this all, one might agree that the two words are perfect synonyms. But the OED, complete as always, continues its definition of serpent, observing that nowadays, in ordinary use, the word is "applied chiefly to the larger and more venomous species; otherwise only rhetorical ... or with reference to serpent-worship."
Therein is the suggestion of reptilian synonymy blown suddenly asunder. For serpent is indeed the word we choose when we want to denote a snake that is bigger and nastier than most, and snake is the word we choose to describe any smooth and elongated creature that skitters from beneath the lawnmower blades. We say, on the one hand, "There is a snake in the basement" and, on the other, that missionaries were once thrown into "pits filled with serpents." But we don't proclaim there to be a serpent in the garden shed, and if we told a listener that a missionary was in a pit full of snakes, we would realize from the resulting questions—Were they big? Were they venomous?—that we had used the word wrongly, poorly, or incautiously. (This leads to another supposed synonymy: venom and poison. The words, however, are not exactly synonymous, because one can speak with venom yet perhaps not quite with poison. Venom is both a substance and a tone; poison is more a matter of chemistry.)