The Oxter English Dictionary by George Stone Saussy III (Facts On File Publications: $15.95). This collection of "uncommon words used by uncommonly good writers" is called "Oxter" because oxter means armpit and, unlike the Oxford English Dictionary, this book is designed to fit under your arm. This explained, you have to wonder just who this book is for. Many of the words included are neither obscure nor uncommon: asperity, beast-with-two-backs, deciduous, miasma or ploy. Many are scatological or sexual, areas in which fancy euphemisms are to be expected: balanic, merkin, merdivorous, omnifutuant and softoff. But many of the words are interesting, and you could wish for etymologies in some cases ( fantods ) and for pronunciation in others ( apocope ) . It is not unfair to point out that the misuse of a word does not legitimize a new meaning: for instance, the use of surd (a mathematical term) to mean "an intensely stupid person." Despite these reservations, the book is fun, and the reader may find himself torn between Alexander Theroux's insistence that these words are intended "not to obfuscate but to clarify" and Frederick Exley's description of the use of many as "sheer pain-in-the-ass pretentiousness."