The Opposite of Sex.

Think Anne Baxter in All About Eve, without the career agenda. Think Barbara Stanwyck in Double Indemnity; without the guile. Think Lana Turner in The Postman Always Rings Twice, without the day job. Think Bette Davis in Of Human Bondage, without the phony English accent.

If you put them all together, you have some notion of Dedee Truitt, the cunning little vixen played by Christina Ricci in The Opposite of Sex. At 16, Dedee makes these seasoned connivers look like Camp Fire girls. In Don Roos's breathtakingly astringent directing debut, this Louisiana miss sets new standards of chutzpah and self-servingness for all of celluloid's white trash women to follow.

You've got to hand it to Dedee: She operates in broad daylight. Narrating her story with bald frankness, she tips us off from the outset that we're in for a bumpy ride. "I do not have a heart of gold, and I don't grow one later," she sullenly admits just moments after flattening her stepfather's fresh grave with a rock and a set of folding chairs.

Then it's toodle-oo to Creve Coeur ("that's French for fucked heart") and hello to the manicured Indiana manse of her 35-year-old gay half brother, Bill (Hollow Reed's Martin Donovan), and his space cadet toy-boyfriend, Matt (Ivan Sergei). Bill is an emotionally sedated English teacher who defends against life's sundry abuses by correcting his tormentors' grammar. Within days of Dedee's arrival, she has seduced Matt, dragged him off to father her child, and indirectly subjected the put-upon Bill to the career-destroying machinations of a predatory teen (Roseanne's Johnny Galecki) who claims to be Matt's other boyfriend.

Given Bill's disturbing Midwestern passivity, we'd explode from the accumulating outrage were it not for a one-woman Greek chorus by the name of Lucia, Bill's doleful work colleague and the sister of his late lover, Tom. As played with withering acerbity by Lisa Kudrow, the embittered Lucia quickly emerges from the sidelines to be the film's most engaging and provocative creation, the gay-friendly confidante who betrays a few prejudices of her own in the name of caring and compassion.

In the face of so much troubled testosterone (there is also a slug-footed cop, played by Lyle Lovett, with a yen for Lucia; and a one-testicled yahoo courtesy of William Lee Scott), Lucia and Dedee provide the movie with needed and refreshingly forthright poles of morality. Exposing hypocrisy and stupidity while watching out for their own butts, they most perfectly embody the crafty Janus-faced act of Roos's screenplay, one that keeps the audience unsteady from start to finish. Three gay-vibed guys walked out of the screening I attended, probably unsure who it was they were supposed to be rooting for. Too bad, because they missed a rabble-rousing burst of homosexual rage that Bill finally lets spill. After Roos's respectable but resolutely commercial scripts for Single White Female and Boys on the Side, he seems positively foaming with anger at what Hollywood leaves unsaid about being queer in America.

The Opposite of Sex is gleefully malevolent fun, crackling with the sort of razor-fine repartee that Billy Wilder and Joe Mankiewicz once patented. It flabs out after the caustic geyser of the first 20 minutes, if only to come up for air, but soon sharpens up for a gratifying windup. And Dedee keeps her promise: Her heart doesn't go gold. It does mush out a bit in the final frames, just when we're feeling totally parched from her merciless tongue. The effect is like sucking on a lemon for an hour and 40 minutes, then being handed a pitcher of ice water, a packet of sugar, and a spoon as we head out the door.