Of the movies currently in theaters, which would you guess features a rarely spoken word denoting an intimate part of the human anatomy? Kinsey -- the frank, lionizing biography of sex researcher Dr. Alfred Kinsey -- would be the logical but false answer. Surprisingly,"perineum" pops up in Mike Nichols's Closer, a movie nearly as explicit about sex, though in service of very different ends.

This barbed chamber work aims to scrutinize modern relationships with bracing cruelty and humor. It succeeds, serving as a bitterly entertaining tutorial on how to use honesty and promiscuity as weapons. Whether that's a lesson worth learning is a matter of personal taste and private morality.

Venturing back into Carnal Knowledge territory, Nichols zaps Patrick Marber's stage play with a jolt of star power and cinematic sophistication, crisscrossing the love lives of four strangers in London:  an obituary writer, Dan (Jude Law); a stripper, Alice (Natalie Portman); a photographer, Anna (Julia Roberts); and a doctor, Larry (Clive Owen).  The four are studied in total isolation; the outside world never intervenes in their affairs of the heart and loins.

If you're looking for tender romance and meaningful eroticism, look elsewhere. Not that the characters don't feel anything or aren't extremely sexy. The crucial dynamic in Closer relates to the consistency or discrepancy between what these smart, beautiful specimens say and what they do in the love arena. A recitation of how their relationships intersect would spoil the experience. Bottom line is they stumble, and their repartee (some of it raunchy sex talk) and actions sparkle with nastiness and ultimately sadness. You're asked to revel in their callousness, suspending moral judgment about their cheating, lying, and, in two cases at least, guilty hearts. An exercise that won't be to everyone's liking.

Chances are reactions will be divided along gender lines. A well-written and executed scene with the two men online in a sex chat room is the first scene I recall in a major movie that honestly captures a prevalent male pastime in our wired society. The ending of Closer, when the notion of a femme fatale is introduced from left field, is its weakest part, at once celebrating and mocking the male gaze.

Nichols is firmly in control, turning things on a polished dime, papering over the elliptical nature of the story's structure with masterly vigor. One major event happens off camera, and the details of how it transpired seem all-important. You want them filled in, but are left to conclude that nothing anyone does can be deemed crucial. Capriciousness is the name of these games.

Owen, who created the role of Dan on stage, wins the acting derby with a ferocious performance as the ruthless dermatologist Larry. Portman finishes a close second, proving there are acting chops beneath her compact beauty. A speech she delivers during an exhibit of Anna's photographs penetrates the movie's core. She complains there's something false about Anna's portraits of strangers. Ascribing emotions to people and turning them into fodder for art seems dishonest to her. And Dan has used her life and their relationship as material for a novel.

This timeless gripe about art applies to Closer, which is an excellent example of imagining lives for no greater reason than that one can. There's no ennobling or even external purpose to the act of creating or watching the movie. Art for art's sake. Closer has a rawness and intensity that might be mistaken for insightfulness. There are flashes, yet as a whole it doesn't say much that hasn't already been said. Nichols's proficiency and his dazzling quartet of actors make Marber's floating themes concerning humiliation and typing -- Alpha versus Beta males; Madonna-whore complexes -- seem deeper than they really are.

Probably nothing can be made of the fact that both females (actresses and characters) are American and both males, British. Nobody realizes his or her romantic and erotic ideals. Likewise audience members don't get any closer to understanding what makes men and women tick. It's brilliant fun trying, however, and years from now people may well view Closer as emblematic of love and sex in our time. The same way we see Nichols's The Graduate or Paul Mazursky's Bob & Carol & Ted & Alice. 

(Released by Columbia Pictures and rated "R" for sequences of graphic sexual dialogue, nudity/sexuality and language.)