A District employer may be held liable under federal law for sexual harassment of an employe by a company supervisor even if the employer is unaware of such conduct, the U.S. Court of Appeals ruled yesterday.

The opinion by the court, a national leader in sex discrimination decisions in recent years, further eases the standard locally for a successful sexual harassment suit under U.S. civil rights statutes.

The opinion ordered the case returned for trial.

"That's fantastic," said Patricia J. Barry, lawyer for plaintiff Mechele Vinson. "It's a step forward. I'd love to try this case in front of a jury."

It is also certain to be cited as a precedent in sexual harassment cases elsewhere in the nation, several lawyers said yesterday.

The 9th U.S. Circuit Court of Appeals in California made a similar finding about four years ago.

The appeals court here ruled in 1977 that abolishing a woman's job because she refused sexual advances was a violation of Title VII of the Civil Rights Act of 1964, which prohibits sex discrimination.

The court was also the first to hold, in 1981, that a woman need not prove that she resisted sexual advances to succeed in a Title VII complaint.

"Today," the court said, "we are confronted by the question . . . whether Title VII imposes upon an employer without specific notice of sexual harassment by supervisory personnel responsibility for that species of discrimination. We hold that it does . . .

"To hold that an employer cannot be reached for Title VII violations unknown to him is . . . to open the door to circumvention of Title VII by the simple expedient of looking the other way . . . "

The unanimous opinion was written by Chief Judge Spottswood W. Robinson III and joined in by Judge J. Skelly Wright and Edward S. Northrup, a senior appeals court judge from Maryland.

It reversed the decision by the trial judge, U.S. District Judge John Garrett Penn, that Vinson had not proved she was the victim of sexual harassment.

Vinson was hired as a teller-trainee in 1974 at a Northeast branch of Capital City Federal Savings and Loan, according to the opinion. During the next four years, she was promoted several times, finally reaching the position of assistant branch manager. The promotions were achieved on merit, according to the trial record.

Vinson left after four years, however, and filed her sex discrimination complaint in U.S. District Court.

In trial testimony, Vinson alleged that her supervisor, branch manager Sidney L. Taylor, asked her to have sexual relations with him, "claiming that she 'owed him' because he had obtained the job for her," the opinion said.

The court said Vinson "ultimately yielded, but only because she was afraid that continued refusal would jeopardize her employment."

Taylor denied Vinson's allegations and contended that Vinson was retaliating for a business dispute, the court said. Capital City successfully argued that it was unaware of the alleged discrimination and had not authorized it.

But, said the appeals court, "Title VII as much outlaws sex discrimination by an 'agent' of an association as by the association itself; put another way, such discrimination by an 'agent' of Capital City is as much an affront to Title VII as it would be if engaged in by Capital City as an entity."

Edward Nylen, chairman of the board and general counsel of the savings and loan, said he had not seen the opinion and could not comment.