Washington architect Arthur Cotton Moore, outlined for a group of Foxhall Road citizens yesterday plans for an unusual development of 120 luxury houses clustered in crescents and circles amid large green spaces on the 25-acre estate of former vice president Nelson Rockefeller.

The citizens have been vociferously contesting development of the estate, which is being sold to the suburban development firm of Rozansky and Kay. After Moore was through yesterday, however, citizen spokesman John Wallach said the plans represent, "A giant step forward. Everyone has emerged from this feeling greatly relieved."

Tommy Jackson, a leader of the citizens, said that some questions remain but that the meeting represented "a step that's way beyond and above" what have been the generally acrimonious relations between citizens and developer.

City planner Kirk White, who also attended the meeting, said it now appears the Rockefeller tract can be developed in a "satisfactory and successful" way. "We're optimistic," he said. Architect Richard Ridley, representing the citizens, said Moore's plans were "very good. . . a very good approach.

However, the citizens refused to let members of the press attend the meeting. "We do not want this open to the public," said Wallach. "This is a fairly sensitive stage we're going through," said Jackson. Both Moore and a representative of the developer said they would be glad to disclose the plans publicly, but did not want to anger the citizens by doing so yesterday.

At one point Mary Barry, a reporter for a small newspaper called The Uptown Citizen, suggested she might "barge through" and enter the meeting uninvited.

"That can't be done," warned the architect's wife, Patricia Moore, as she confronted Barry in the firm's modern Georgetown office. "Yes it can," countered Barry. "No it can't, said Moore. Barry then subsided.