The U. S. Court of Appeals, in a harshly worded opinion, yesterday reversed a lower court decision in which a former employe of the Library of Congress, who masqueraded for years as a lawyer, successfully argued that his civil rights were violated when he was fired for his job.

The employe, copyright examiner Joslyn N. Williams, received no benefits from his ruse. But Judge Louis F. Oberdorfer, in what he described as a "unique remedy" for the alleged discrimination against Williams, told the library to set up a fund so that other employes could hire lawyers and specialists to help them with discrimination complaints. Oberdorfer's order in 1978 was believed to be the first of its kind in a discrimination case.

Now, however, with the Appeals Court ruling yesterday and the earlier refusal by Congress to implement the fund, Oberdorfer's order "is as moot as it is 'unique,'" Appeals Court Judge Malcolm R. Wilkey commented in a footnote in his opinion yesterday.

Oberdorfer had ruled that Williams sbasicalaly proved his claim that he was discriminated against and subsequently fired in retaliation for his outspoken criticism of alleged racial discrimination in employment practices at the library.

Wilkey said the Appeals Court accepted Oberdorfer's finding that Williams was a "leader" and a "symbol to blacks" who worked at the library where Williams was a "powerful proponent of the rights of black employes. . ." w

But, Wilkey wrote a 21-page opinion, "neither these accomplishments, nor the personal tradegy exemplified in Williams' rise and fall, however, convert this unsuccessful masquerade" into a valid discrimination case.

At the trial level, Oberdorfer had said that library managers may have taken a harder look at Williams, when questions were raised about his legal capabilities, because of his anti-discrimination efforts. But Wilkey said yesterday that Oberdorfer had found "no act, word or deed hostile or discriminatory to Williams . . . prior to (the library's) discovery of his career of complete deception."

Wilkey recounted that Williams falsely claimed he had three years of legal training at Georgetown University, misrepresented his academic record at Howard University, requested leave to study for the Maryland Bar Examination and "perpetuated" his story in each of four job applications.

"Naturally -- or at least reassuringly -- it was discovered eventually that Williams as a lawyer was a fake," Wilkey wrote.

"An egregious record like this one hardly poses the ideal case for a whisper of a rarcial discrimination complaint, let alone an employment discrimination lawsuit," wrote Wilkey, who was joined in his decision by Judge Edward A. Tamm and Senior Judge David L. Bazelon.