With some startling revelations, the French have put the word sexy back into the fashion vocabulary.

Even Yves Saint Laurent, whose spring collection shown today replayed many of his favorite themes of the past 20 years, found ways to make his clothes sexy. He showed head-to-toe see-through dresses and daring blouses under business suits; he left buttons unbuttoned at the back of skirts; and he put many models in dark, sheer pantyhose and pumps.

If sexy is the way women want to look, the French designers spared no gimmick to oblige them. They:

* Bared midriffs and shoulders with halter tops, cutouts and slits.

* Emphasized hips with tight skirts, belts and hip yokes -- and hip wiggles by models to show them off.

* Showed underwear as outerwear with bras as tops, girdles as belts and vests like men's undershirts.

* Cut off hems at the knee, often with buttons or deep slits at the back to emphasize the rear view.

Chanel, which once liberated women with knit suits and jersey dresses, has gone totally tootsie with skinny skirts, see-through dresses and an overdose of jewelry.

The clear favorites among the French are Claude Montana, who has abandoned his extravagant costumes of past seasons for more wearable (and salable) styles; Sonia Rykiel, a master with knitting needles who knows how to make clothes look sexy, the way she likes to wear them; and Jean-Charles de Castelbajac, who has always been partial to uncluttered, easy clothes.

With the exception of Saint Laurent, who has been resting after a hectic season celebrating his 20th year in business, ruffles and romance are gone from most of the collections -- the ethnic look has been passed over, leather clothes have been skipped over and jogging clothes are clearly off the track.

Big shoulders continue, though scaled down from their earliest incarnation; hems are varied, and the very short dance dress has become the way to show up at the dressiest party in town. Pants are mostly slim and above the ankle, and always present. "It could make no more sense to make a collection without pants anymore than a collection without skirts," laughed Karl Lagerfeld at Chloe'.

Charlotte Rampling, the model and actresss who was in the front row of Yves Saint Laurent's show wearing trousers and a trench coat, said she might wear YSL's Bermuda shorts in the city, but as for clothes that are short, tight and sexy, "They may be interesting to look at, but for me, impossible to wear."

But, according to Bruce Binder, a Macy's vice president who has lived in Europe for many years, European women love the look. "I love it too," Binder said. "But can the woman who is liberated see herself as a sex symbol again?"

Paloma Picasso thinks so. "Being liberated or not is very inside," said Picasso, who was wearing a long-and-easy leather skirt, but who likes to wear YSL's short-and-tight black-leather style. "You don't take such a position with your clothes."

"There is no such thing as a liberated woman when it comes to fashion," insisted Judith Krull, the personal shopper at Bloomingdale's. "I'm wearing high heels. My feet kill me and I think I look terrific."

Val Cook of Saks-Jandel said, "It will make many more women, including me, spend more time at the Jane Fonda workout."