It's not how clothes cover the body but how they reveal it that figures in what Washington women are wearing this summer.

Slits on the right or left, front or back, or sometimes a combination highlight everything from success suits to separate skirts to dresses and even jean styles.

Slit skirts from Anne Klein and Calvin Klein started to sell in Washington by early last fall. And while New York has already moved on to shorter skirt lengths that require shorter slits or no slits at all, Washington women still like the longer slim styles with deep slits that give mobility as well as a sexy look.

Recently, on Connecticut Avenue during the lunch hour, skirts with slits were almost as popular as the many full-skirted styles.

"I like them because they are feminine and comfortable," said Kathy Jens, who works in the sakes division of the Sheraton Fredericksburg.

"I wear them simply because it's the style," said Patricia Kellam, a bookkeeper at the American Textile Manufacturer's Institute.

What Donna Ebert does is simply adjust the pattern for the clothes she makes for herself. "Many of the Vogue patterns are simply too slit for me," said the production coordinator for Mark Battle Associates.

Elizabeth Sauders, manager of Panic Press, admitted she tilts to deep slits because they are sexy. "But I wear careful about which slit skirt I wear when," she said. "If I am going to see a client, I make sure they are not too sexy."

Gloria Feldman, a legal secretary, didn't pay much attention to the slit when she bought a jeans skirt. "I only wantnd to be sure that a jeans skirt would be proper for the office," she said.

Barbara Houston, secretary for a health insurance lobbyist, plans to make her next slit skirt purchase the button-down variety "but I'll probably never open it beyond the bottom button." Her big problem now is findng slips with slits that slit where the skirt also slits.

"They make a lot of slips with slits," she said. "The only problem is that the slip slips around, then all you see is the slip not the slit." So she said, without a slip of the tongue. CAPTION: Pictures 1 through 5, Washingtonians in their summer slit skirts, clockwise from bottom left: Gloria Felaman, Donna Ebert, Elizabeth Sauders, Patricia Kellam and Kathleen Jens; By Tom Allen