It's as if the Paris designers had called their New York counterparts and said, "cut skinny." The message is clear: Women want skinny clothes again. Designers believe, and most store buyers agree, that shape is in, and indistinct, overblown silhouettes are finished.

These are the final fashion presentations of women's spring and summer clothes that started a month ago in Milan, took on steam in Paris, continued in London and wind up here next week. At each location designers have made the point that women are in shape and want to show it off, with clothes that fit tight to the body, marked waistlines and narrow skirts, usually cut off just below the knee and often slit.

Not everyone entirely agrees. "To say that loose clothes are wrong would indicate that we were dishonest last time," says Geoffrey Beene, who continues to show soft-shaped clothes, though not as full as in the past. "I believe in big clothes. Women should not throw them out. There is nothing like them in the summer-time," Beene says emphatically. But he is in the minority of designers seen to date.

As well as the slimmer shape of things to come, New York shares the Paris shows' penchant for offbeat settings.

Bill Kaiserman expects buyers and press to race to the New York passenger Ship Terminal at 5 p.m. tomorrow; an hour later the Charles Suppon show takes place on West 27th street; and then at 8 Beene will show his collection at Lincoln Center.

And for yesterday's opener on Seventh Avenue, Perry Ellis set up bleachers in the undecorated space soon to be his showroom - with buyers and press jammed to the rafters. Formerly a branch of the Chase Manhattan Bank, with floor-to-ceiling windows and marble pillars, the setting is appropriate: His last two collections have been money in the bank for the stores that have featured them ... and Washington stores are no exception.

This was Ellis' first collection independent of Vera, and clearly one of the best. Forget about the pantyhose cut off at the knees and other such experimenting that really doesn't work. Lots of things work marvelously well.

Ellis, who was passed over in this year's Coty Awards (and many in the audience booed when the announcement was made), is a terrific sweater designer. His spring designs are almost all in cotton, many cut short at the waist to bare a bit of the midriff, or so brief as to be strictly a bandeau. The skinny skirts he started showing for fall are already selling well, and they are equally appealing for spring, often with the big-shoulder belted jacket. And his suits with a sweater underneath proved just as popular yesterday when the bottoms were ankle-length tapered pants.

"I can see so many people wearing his pedal-pushers and knit sweaters," says Mimi Liebeskind of Ann Taylor. She'll also have some of the Ellis pleated miniskirt in stock for those who like to run all over the town in tennis dresses or golf skirts.

Koko Hashim of Neiman-Marcus says, "The man has finally established that there is another element of style apart from the establishment. It's a strictly casual attitude about clothes that lets you put on clothes and then forget about them."

Models in the Ellis show were drinking pink champagne for the last segment. Pink was the color theme, including a pink linen suit for bridegrooms and pink veils for mock-brides. The designs were casual indeed, occasionallly letting jackets fall open to reveal a bare chest, or letting skirts flip up to show white Fruit of the Loom panties.

Things were far less casual at Bill Blass, where body-conscious clothes for a more mature (and wealthier) customer were shown to buyers and press sitting sedately on plexiglass-and-chrome chairs in a room sprayed with the new Blass perfume.

Blass revived some old-time concepts like coats with matching skirts, coordinated blouses and diamond clips. But the best of Blass had little that was reminiscent about it, particularly the opening gowns with their blocks of bright colors - like a strapless with tight red bodice, bright purple skirt and red jacket.

Ellis put lace gloves on his models for fun. But Blass' customers will probably wear the near-elbow-length glace leather gloves and little hats he offered them.

"Right now we are selling hats and belts extremely well, so we think Blass is right on target," said Gerry Blum of Lord & Taylor. Blum is convinced that women want to show their legs through the deep-slitted skirts ("Maybe not as deep as in the show") as well as bare arms and bare necks. "Women have been taking good care of their bodies. Their skin has never looked better and they want to show it off," insists Blum.

"Women just want to look sexy again," says Blass. And he certainly is offering them the chance.

Buyers are still uncertain about costs, since price sheets are seldom given out at these shows. But from all indications, they are bound to be up. "I ask about prices, but it has to be incidental," says Ellis. "The important thing is to achieve the look I want."