The study of semantics involves a determined precision in the intent and application of words. Mr. Pei, a fringe-semanticist of prodigious output, is here dealing with terms loaded far out on what Hayakawa would call the ""abstraction ladder"" or what Pei calls ""weasel terms. . . terms that have undergone a shift of meaning by deliberate action on the part of groups with an axe to grind."" Mr. Pei investigates popular tags in the fields of education, politics, advertising, young slang, etc. with his own grinding axe whirring away. He refers to the terms, ""underprivileged"" and ""disadvantaged"" as ""two other words favored by the do-good variety of left wingers."" In offering his own inventions like ""intellectuous,"" Pei defines it as ""what is pseudo-intellectual. . . a pose. . . by our more pompous scholars and know-it-alls."" A megatonnage of minithink, weaseling-in as semantics.