Is there a woman alive (over 25) who doesn't approach the swimsuit department nervously?

Some have some luck after a few try-ons, but others -- more than a few we know -- are so discouraged by the skimpy, bantan-weight suits hanging in stores, they give up and retreat to last year's models in their own closets.

While they may not appear so on the rack, many suits have built-in disguises for the less -- or more -- than model-size figures. Totally limp and shapeless styles are difficult for most figures, but the pared-down maillot often has details which can fool the eye and be more flattering than sometimes-dowdy dressmaker suits.

Some other reminders on buying a swimsuit:

Stiff cups often exaggerate a large bust; a flat band across the top flattens a small one.

High-cut sides make legs look longer and can help disguise chunky thighs.

Random patterns can keep the eye away from the figure problem at hips, bust, waist.

Front gathers can hid a less-than-flat stomach.

Ruffles or flounces add fullness to the bustline, or balance a pear-shaped figure.

Overblouse tops and skirts are the predictable solution for generous tops or hips.

Deep cleavage and wrap styles flatter the top-heavy figure.

Check labels for fiber content. The style with more spandex is apt to offer more control. Nothing is more important than to try on lots of different suits, even those you don't expect to be flattering. CAPTION: Illustration 1, Overblouse: De-emphasizes bust and hips. Two-piece suit by Parform/Astra, Raleighs, $30.; Illustration 2, Classic Disguise: Skirts the issues. Classic skirted suit in flower print by Gabar, Lord & Taylor, $51.; Illustration 3, Diagonal Ruffle: Maximizes bust, minimizes midriff. Assymetrical ruffle suit in navy and white by Gottex, Bloomingdale's, $52.; Illustration 4, Center Shirring: Camouflages a stomach that isn't flat, or a bust that is. Turquoise nylon and spandex suit by Cole of California, the Bikini Shop (1136 18th St. NW), $33.; Illustration 5, Wrap style: Pares down pear shapes. Surplice-wrap stripe by Jantzen, Hecht's, $38.; Illustration 6, Stripes: District the eye from anywhere. Strapless navy and white stripe suit with high-cut legs by Gottex, Woodward & Lothrop, $54.: Illustrations by Martha Vaughan.