A student at George Washington University Medical School who was expelled two weeks before her scheduled graduation sued the university yesterday, alleging that the dismissal was based on her race and personal appearance.

According to the suit, filed in D.C. Superior Court, Lillie NW, had received failing academic evaluations, and also was found lacking under non-academic considerations, such as her appearance, acceptance by colleagues and personal style.

Following an 18-day clerkship at the Psychiatric Institute in Rockville, the suit said, Walker's supervisor wrote a report recommending that she be failed in that course. The suit quoted the report as saying that "at times she would wear clothing which was inappropriate in that she apparently gained weight, and her clothes were clearly too tight;" that "she was moralistic and judgmental of patients," and that "she would frequently sit in patient meetings, starting, with her eyes rolled up toward the ceiling - a very bizarre-appearing bit of behavior."

Walker, who is black, said the decision to dismiss her for academic reasons was "discriminatory, an abuse of discretion and made in bad faith." She said she had passed all her courses during the four-year curriculum except for the 18-day clinical course. She said she now owned $25,000, borrowed to pay her way through medical school.

Walker said she had been accepted at the State University of New York for her psychiatric residency, but that would be canceled because of her dismissal.

In a prepared statement, lawyers for George Washington University said, "We have not read the complaint and are not in a position to comment on it."

The statement said further that the substance of Walker's allegations were considered during a 12-hour hearing before the George Washington University grievance review committee. It was decided, the lawyers said, that Walker was not dismissed for reasons of racial or sex discrimination.

Walker was notified May 11 that she had been expelled. Graduation was set for May 27. According to the suit, the dismissal was based solely on failing the clerkship in Rockville, where no other George Washington University Medical School student had ever been sent.

"All of the patients at the Rockville Institute are white," the suit said, "and every member of the full-time resident time resident staff, with the exception of one Oriental, is white." Walker said that none of the staff members consulted for the evaluation had spent much time with her, and the Oriental on the staff, with whom she did spend time, was questioned only briefly.

Walker said that while working in Rockville, she was prejudged as a "marginal student," and was not allowed to examine or treat patients on an individual basis. Attending patients, Walker said, forms the criteria upon which a successful clerkship is based.

Walker said she had been accepted for a medical school clerkship at Mt. Sinal Hospital in New York and would have preferred to work at St. Elizabeths Hospital in Washington rather than go to Rockville.

The suit said she was told to go to the Rockville facility for closer supervision by staff members known by George Washington University officals.

According to Walker's lawyers, Linda Singer and Ronald Goldfarb, the case will be hard two days before the scheduled graduation. They are asking that Walker be reinstated.