By RUTH LA FERLA

Pretty in pink? Not Deborah Watson. “If I see a floral print or pastel dress in my closet, I think: ‘Ugh, gross! I don’t want to wear that,’ ” she said. Ms. Watson, a fashion stylist in New York, has turned her back on those hallowed totems of femininity in favor of the raffish look of a big T-shirt, well-worn jeans and a graying black cotton overcoat. “Anything more girly, I just see as weak,” she said. “It’s not cool to be demure.”

A disdain for such sweetly conventional trappings of sex appeal has trickled down of late from tastemakers like Ms. Watson to scores of followers who are swapping their babydoll dresses, spindly heels and lace for the flinty attractions of studs and leather, mannish jackets and rockstar jeans. Their embrace of a pointedly aggressive, street-smart style suggests that the more adventurous are rethinking the tenets of female allure.

If the old ideal of sexiness was the shoulder-baring voluptuousness of Scarlett Johansson, the new sexy is the European fashion editor Carine Roitfeld in a black blazer and tall vixenish boots. The look, often slightly disheveled, is shared by off-duty models and style-world insiders.

Women now want to project a “more powerful sexuality, not a damsel in distress,” said Sharon Graubard, a senior executive with Stylesight, a trend forecasting firm in New York. The look, streamlined and armored for tough times, reflects a distrust of trends and a skepticism toward traditional gender roles. Most tellingly, perhaps, it also represents a pragmatic response to a hobbled economy.

“So-called luxury - people are tired of it,” said Tatsugo Yoda, the owner of Aloha Rag, a fashionably progressive Honolulu boutique with a New York outpost. “They want more utilitarian pieces - military jackets, track pants and classic white shirts - that they can wear more than twice a year.” The look is assertive, Mr. Yoda said, but recognizable at the same time.

Much the same can be said of the 1990s-inflected biker jackets, latex leggings and fingerless gloves that are also key components of a style that is as racy as it is familiar. It represents “a down and dirty kind of look,” said Andrew Bolton, curator at the Costume Institute of the Metropolitan Museum of Art. At the same time, its suggestion of disarray “gives an idea of accessibility,” he said. “There is so much sex appeal in imperfection.”

These notions of sexual allure can be traced to the utility gear adopted by self-styled survivalists, the funky regalia of old-school rockers, even the lingerie-and-leather of Parisian streetwalkers. These rebellious, antifashion messages, blunted over decades of exposure, have been picked up, inevitably, by the world of high style.

Today shapeless, and sometimes shredded, T-shirts, combat boots and aviator caps reminiscent of a Mad Max epic are proliferating on runways, as are leggings, fatigues and bicycle shorts. At the same time, retailers are championing the studiedly casual look of tailored jackets, oversize tunics and understated dresses as unfussy correctives to the rumba ruffles and dolly-bird frocks still appearing on some runways. This fall, fast-fashion outlets like Topshop and Forever 21 offered myriad variations on the biker jacket, leather rocker vest and calf-clutching jeans.

The look also reflects a willful gender mash-up being propagated by the young or young at heart.

“We’ve got a new dress code based on shifting norms around gender,” said Diane Ehrensaft, a psychologist in Oakland, California. Dr. Ehrensaft, who sees many middle school students and teenagers in her practice, argues that their blurring of assigned roles is deliberate and calculated. “Younger people just aren’t accepting the standard boxes anymore,” she said.