Former D.C. City Council member Douglas E. Moore said yesterday that he is stepping aside from District of Columbia politics for a while and going into "the oil business" with a cousin in Spain.

"I'm going to try to do what I can to help people," Moore said, suggesting that some of the money he earns from his business activities might be funneled into populist political causes here.

"I'm not retiring from anything," Moore said, "Except I realize that our problem, basically, is economics."

As he often did on the campaign trail, Moore mentioned that there are 17 teachers and two principals in his family. "We've had a strong educational and political thing," he said. "Now we're going into economics."

Despite two stunning defeats in less than a year, Moore would not rule out running for office in the future. (He will not live in Spain, he said).

"If I would ever go into electoral politics again, I would have to campaign and bring a lot of family money or my own money into the thing," Moore said. "In light of the reality of the media and that sort of thing, you have to have additional money. It's not enough to go on a $15,000 campaign."

A calm and occasionally yawning Moore telephoned a reporter early Wednesday morning, less than nine hours after he conceded defeat in his desperate effort to make a political comeback by running for an at-large City Council seat in Tuesday's special election.

Tuesday's loss was by a slightly larger margin than in Moore's losing bid last year to win the Democratic nomination for City Council chairman. The latest defeat came despite an effort by Moore's advisers to run a low-key, issue-oriented campaign for fear that Moore's fiery political rhetoric and past scrapes with the law would work against him.

Moore was not bitter about the loss. "If you're strong on the issues, losing itself is not the end of everything," he said. "I'm very secure. I have no anxiety about anything. I'm very relaxed. I don't have to worry about money."

Tuesday's defeat was not only a personal political setback for Moore, the colorful and controversial 50-year-old Methodist minister and chairman of the activist Black United Front.

It also was the third straight major defeat for the loose-knit band of housing activists and community organizers who have tried to build a populist political movement in the city, with the help of organized labor and some churchmen.

In 1977, former school Supt. Barbara A. Sizemore, carrying the group's mantle, lost her effort to win an at-large Council seat. Moore lost for chairman in 1978, and for council member this week.

The lesson of those defeats, according to one person intimately involved with Moore's campaign who asked not to be named, is that the populist movement here is leaderless and lacking the kind of sophistication that home rule politics has obtained in the past five years.

"I don't think the populist movement is dead. But the people who respond to a populist stance on economics issues are people who won't vote, and you need some leadership, too," the source said.

Moore, the architect of Sizemore's strategy who often has portrayed himself as a political disciple of the late Julius W. Hobson, had become the most persistent candidate for that leadership.

But the last campaign showed, the source said, that Moore's own past - including his frequent scrapes with the law, one of which resulted in an assault conviction for biting a tow-truck driver outside the District Building - was a burden to the movement.

"The people who respond to a populist political movement all over the city couldn't deal with the excess baggage that Doug had," the source said. "People didn't forget the tow truck operator."

Moore would not talk further about his cousin in Spain or about what kind of work he would do. He did say, however, that he had made two overseas trips related to the business during the past year and had been actively talking with the cousin even during his campaign.

In the last campaign, Moore sought the endorsement of the Metropolitan Washington Board of Trade, once the principal target of much of his verbal scorn, and also accepted more than $2,000 from some of its members.

He said he stretched his own criteria on sources of campaign finance to their limits and still got little financial support. "I kept asking where are all the liberals?" Moore said. "How can they be liberal and not support me?"