tautology, redundancy, pleonasm, solecism

   Although various authorities detect various shades of distinction between the first three words, those distinctions are always very slight and, on comparison, frequently contradictory. Essentially all three mean using more words than necessary to convey an idea.

   Not all repetition is bad. It can be used for effect, as in poetry, or for clarity, or in deference to idiom. "OPEC countries," "SALT talks" and "HIV virus" are all technically redundant because the second word is already contained in the preceding abbreviation, but only the ultra-finicky would deplore them. Similarly, in "Wipe that smile off your face" the last two words are tautological-there is no other place a smile could be-but the sentence would not stand without them.

   On the whole, however, the use of more words than necessary is better avoided, although it can be found even in the most respectable usage guides, as here: "All writers and speakers of English, including these very grammarians themselves, omit words which will never be missed" (Bergen and Cornelia Evans, in A Dictionary of Contemporary American Usage). The expression "these very grammarians themselves" is patently redundant. It should be either "these grammarians themselves" or "these very grammarians" but not a combination of the two.

   Finally, solecism describes any violation of idiom or grammar. Redundancies, tautologies, and pleonasms are all solecisms.