In the old days, when squash was played just by Ivy League alumni on pleasantly rundown courts, the clothes of choice were an old college T-shirt and a pair of soccer shorts. The look was endearing, and the opponents never felt intimidated.

But today squash is less collegial, more combative. And a racier more competitive look can easily be found among tennis wear. Since squash is played indoors, clothes should be of lightweight cotton fabrics and flexible for the fast pace of the game.

For footwear, squash players should choose shoes with rubber soles that are comfortable and durable.

Tournament players are now required to wear eye guards. Available with or without lenses, these glasses provide an extra measure of protection for serious players.

Tennis players still seem to dress in conservative whites; raquetball players have a more macho, shirt- hanging-out look. It's the squash court where fashion shows a new set of challenges. CAPTION: Picture, WINTER SQUASH: royal blue wool vest with light blue, black and white stripes, $48; short-sleeve with blue collar $45; white cotton-blend shorts with striped waistband, $39, all by Head; thick Thorlo socks, $6,50, eye guards by Leader, $25. White cotton-blend shirt with green pin stripes, $35; white cotton shorts with terrycloth-lined pockets, $35; all by Descente; thick Thorlo socks, $6.50. All squash clothes at Drilling Tennis Shop. Photograph by Peter Garfield