The Virginia State Bar, discovering itself on constitutionally shaky ground, has withdrawn a complaint it filed last year against Sol Z. Rosen, a Washington lawyer who repeatedly has accused the bar of discriminating against women, blacks and Jews.

"The bar believes it appropriate to withdraw against Mr. Rosen and . . . to review [its] rules in light of Constitutional issues," the bar said in a court notice dropping the action.

The complaint against Rosen, which could have resulted in his disbarment, accused him of violating a rule that allows lawyers who have practiced elsewhere for five years to practice in Virginia without taking bar examination providing they work full-time in the state.

Rosen conducts his practice from his downtown Washington office, although he has stationery with an Arlington letterhead.

"When you analyze the rules, they are unconstitutional," said Rosen's lawyer, Philip J. Hirschkop of Alexandria. "There is no logical distinction between people admitted on motion and those not . . . Such rules are a real inhibition to a modern-day law practice."

When the complaint was filed against him last summer, Rosen claimed the bar was retaliating for a suit he had filed against the bar in U.S. District Court in Alexandria. The suit was dismissed and the 4th U.S. Circuit Court of Appeals refused to review it.

Yesterday, Rosen clearly reveled in his victory over the bar. "They used me as their whipping boy until Hirschkop clipped their wings," he said gleefully. "This is not the end . . . I'm just going to keep fighting to make the bar more democratic."