Some are calling them "underalls for men."

Others, the "next thing to Eldridge Cleaver's cod piece . . . but at least the cod piece is independently washable."

Whatever. The Brooks Brothers "invention," straight from their design board, is unheard of (in present form) in the annals of menswear.

Now that you're breathlessly awaitiing the what . . . we're talking about the "Unique New Trousers," as Brooks calls them, with built-in undershorts, not unlike swimtrunk liners.

In a letter to charge and mail-order customers Brooks Brothers vice president Alfred M. Schmidt calls the trousers "a practical alternative to toting extra undershorts when you want a quick, handsome change of clothes after sports or when traveling."

The trousers themselves ($32.50) are white, tan or navy in a polyester cotton blend that is a machine-washable and as the promotion piece says, "stitched into the trousers, our very comfortable nylon knit briefs."

Since you often have to wash white or tan trousers after each wearing anyway, dunking the built-in underwear along with the rest is no problem, according to some prospective customers.

"And for those who care about the line of their undies showing through their trousers," insists a Brooks regular, "these are an advantage, too."

"But," he adds after a pause, "is that really the Brooks customer?"

Maybe, but even one Brooks Brothers executive was startled when told of his company's new design. After an audible gulp, he asked, "Did we really do that?"

Defending the idea -- with humor appropriate to what is, granted, an innovation that will hardly shake the world -- is David Waters, chairman of the board of Garfinckel's, Brooks Brothers, Miller & Rhoads, Inc. The idea for the pants-cum-liner, he says came from a Brooks Brothers buyer-sailor, who saw its practical appeal for serious sportsmen.

"No," concludes Waters with a smile. "We are not becoming the Frederick's of Madison Avenue."

On the other hand (or leg), remember the first time you heard about drip-dry?