More than 10,000 persons attended outdoor commencement exercises at Georgetown University here yesterday and heard humorist Art Buchwald give the 1,600 degree recipients some tongue-in-cheek advice.

The syndicated newspaper columnist, who delivered the main address, suggested that those who subscribe to the nostalgia craze should pretend today is yesterday and "just go out and have one hell of a time."

Buchwald was among ten honorary degree recipients. For the first time, they included two Washington-area secondary school teachers who were chosen by vote of students at Georgetown.

The two were Sister Mary de Sales McNabb, of Georgetown Visitation Preparatory School, and Grace Hendry of Walt Whitman High School in Bethesda. Sister de Sales teaches computer science and Mrs. Hendry teaches social studies.

They were chosen in balloting conducted among Georgetown students who were graduates of their schools.

A Georgetown spokesman said the awards to secondary school teachers will be continued in coming years and extended to other geographical areas as a means of recognizing the teachers' educational contribution.

Other recipients of honorary degrees included Egyptian Ambassador Ashraf A. Ghorbal; former Boston Celtics basketball star Bill Russell; new Catholic University President Edmund Pelligrino; Dean Edmund Gullion of the Flecther School of Law and Diplomancy at Tufts University; Nobel prize winning physicist John Bardeen; Paul Hume, misic critic of The Washington Post, and Meg Greenfield. The Post's editorial page editor.

In his talk, Buchwald alluded to a 1977 dispute in which he had written a letter to a student newspaper. The letter criticized Georgetown for accepting a $750,000 gift from Libya, which he had called a supporter of terrorism. Buchwald described himself yesterday as uncertain whether his award was to co-opt him or to honor his letter-writing brilliance.

The irreverent style of the commencement address was exemplified by Buchwald's acknowledgement of Richard McCooey, owner of a restaurant near campus, who received a medal honoring alumni service to the university.

Buchwald said McCooey's "drinking establishments" had "done more to get Georgetown students through school than the faculty sitting there today." He got a standing ovation. CAPTION: When Georgetown University bestowed the honorary degree of doctor of humane letters on former Boston Celtic basketball player and coach Bill Russell yesterday, the Rev. Aloysius Kelley, right, found he could not reach high enough to place the doctoral degree hood around Russell's neck. The athlete solved the problem by bending his knees. The Rev. Timothy Healy, president of Georgetown, left, assisted in the presentation. Photos by Linda Wheeler-The Washington Post