DEFINITIVE, DEFINITE. Speaking last November in connection with the proposed Goods and Services Tax, Revenue Minister Otto Jelinek remarked that the "only definitive thing" he could say was that the legislation would pass by the beginning of the year. Definitive, which means final or unconditional, was an inappropriate adjective, since at that time there was no way of predicting what amendments or exemptions might be adopted before the tax came into force, even assuming that it would eventually do so. Setting aside the minister`s hesitant use of the qualifying only, what he probably meant to say was definite, a word indicating clearness or certainty, as opposed to vagueness or doubt. DIFFUSE, DEFUSE. In January the Financial Post reported the acceleration of diplomatic efforts to diffuse the Persian Gulf crisis. The ordinary meaning of this verb is to disperse or spread out. Although defuse was once an acceptable spelling variant of diffuse, and it survives, for example, in Shakespeare`s plays, it is now obsolete for that purpose. Defuse, in the modern sense, means to remove the fuse from an explosive device; its figurative application to dangerous situations is a natural extension of literal usage. Perhaps it is arguable that a crisis can be reduced, or even averted, through diffusion, but defuse is better and more forceful. DISCREET, DISCRETE. Advertisers in the Companions columns of daily newspapers are often self described as discrete persons who seek and expect that quality in others. Discreet is evidently what they have in mind to claim those admirable traits of circumspection and good judgement. At one time, the spelling discrete was the prevalent form. Not only did it signify what we now understand as discreet, but it also meant, as it still does, separate or discontinuous. By the late 16th century, however, discrete and discreet had assumed their present distinct roles. Four hundred years later, there is no excuse for confusing two entirely different concepts. Those who mistakenly advertise themselves as discrete may display nothing more than their failure to have it all together. FLOUNDER, FOUNDER. Negotiators should worry about the future of developing countries if the GATT talks flounder, warned a U.S. trade official last year. At about the same time, it was announced that although the annual number of bank failures in the United States had recently declined, the foundering economy of that country might prevent any sustained improvement. Flounder means to struggle, something which all multilateral trade discussions are almost certainly bound to do at some stage, despite their ultimate success. Founder, meaning to collapse or fail, was the circumstance against which the official should have cautioned his colleagues. Similarly, while the present U.S. economy could be fairly said to /founder, there would be no justification for accusing it of foundering. GAMBIT, GAMUT. The chairman of the Writers` Union of Canada informed the membership, through the organization`s newsletter, that a recent meeting between TWUC and Canada Council had covered the gambit of the issues to be discussed. TWUC members may well regard themselves as mere pawns at the mercy of that powerful dispenser of grants to writers, but gambit should be confined to describing an initial stratagem in chess, or some other situation where a clever opening move leads to later advantage. The chairman ought to have chosen gamut, meaning the entire range of a thing, to identify the scope of TWUC`s concerns. On the other hand, he may have been thinking of ambit, a limit or extent. MITIGATE, MILITATE. Irving Layton was quoted by Peter Newman in a Maclean`s column as saying that Pierre Trudeau`s class and education mitigate against him. Militate should have been used instead. Mitigate means to lighten or moderate, as in the lessening of a criminal punishment. Militate, which derives from the same source as military, means to struggle or conflict. It is normally followed by against, and the word itself rarely implies action in favour of a particular course or result. NAUSEOUS, NAUSEATED. The performer of a radio or television commercial who professes to be nauseous, as the prelude to recommending a particular brand of stomach soother, may be speaking with unintentional accuracy. Yet the argument that nauseous means causing nausea, while nauseated means affected by it, is disputed by some permissive authorities. Webster`s Ninth New Collegiate Dictionary, for example, corrects and castigates those pedants who dare to confine nauseous to a single meaning, and it inexplicably regards nauseated as being little used. It is quite true that in 17th-century England, nauseous was sometimes treated as a synonym for nauseated, but the practice has long been out of favour in that country. Surely it is common sense to distinguish between two words, neither of which should be unfamiliar to anyone, instead of making one of them do a double, ambiguous duty.