It was Shirley Chisholm, a small spotlight shouting an emotional farewell to a ballroom of 3,000 blacks, who best defined the fury and frustrated tears. "I am giving up my House seat," the 14-year congresswoman from Brooklyn told her colleagues during the 12th annual Congressional Black Caucus weekend, "but I am not -- I AM NOT -- abandoning the dreams of Dr. King."

The crowd at the Washington Hilton gave her a thundering ovation and afterward called her speech "inspiring" and "gorgeous." But 24 hours earlier, sitting in the middle of a small knot of reporters, Chisholm's words had been those of a weary politician. "I'm a popular woman," she said, "but a lonely woman. I've given 25 years of my life to the cause. I want to go home and be like millions of other Americans, to sleep until 10 or 11 on a Saturday or Sunday if I so desire."

"You know what her speech said to me?" one black politician ruminated in the swirl of pageantry on Saturday night. "She's had it, that's all. Just had it."

In a sense they all had. Nearly 8,000 of America's black leaders assembled in Washington this weekend, feeling abandoned by the current administration and some of their fellow Democrats as well. But to the 18 black members of Congress who make up the caucus, Ronald Reagan was the principal villain. At the legislative workshops, a tearful prayer breakfast and the late-night round of parties, the message came through: They've long given up on Reagan and can only hope that his economic and social policies affecting blacks will now alienate him from whites.

"We peeked into his game long ago," said Rep. Harold Ford (D-Tenn.) "Now white America is finally realizing that Reagan is a phony."

"He has no credibility in the black community," said Rep. Julian Dixon (D-Calif.), organizer of the weekend.

"Reagan's not misinformed," said Rep. Charles Rangel (D-N.Y.). "Reagan doesn't distort the truth. He lies."

But in the midst of the anger, the politicking and deal-cutting continued at a furious pace, almost as if to spite the current gloom. There was steak tartare at a lavish reception for Chisholm on Friday, male models at a fashion show on Saturday, spicy Bloody Marys at the private brunches yesterday. There were beautiful suits and silks. Criticized in the past for the extravagance of the weekend, these are establishment blacks keenly aware that their seminars on the poor and unemployed seem out of sync with the expensive, carnival-like air. But as Ford put it:

"I don't think Reagan should deprive us of the American dream . . . we always felt that we should have been the ones sipping the mint juleps -- not the white folks. We're proud of the fact that we can come here. It shows that the justice system works."

Whether or not the weekend itself works was an open question. Jesse Jackson grumbled about the lack of focus, and Atlanta Mayor Andrew Young, asked if he were completely happy with the weekend's format, flatly said "No."

The weekend's principal purpose is to raise funds for the caucus foundation (it's expected to net almost $400,000 this year), as well as to allow blacks to learn of new laws affecting minorities. But although the caucus members say they can set legislative strategy from what they heard in the Friday workshops, there is still no formal agenda coming out of the weekend. "I think that's probably the next step," said M. Carl Holman, president of the National Urban Coalition. Success Story

On Saturday night, just as he was sitting down to the awards dinner, T.M. Alexander Jr., a vice president of E.F. Hutton in Atlanta, took time out to explain one of the benefits of the weekend.

"Three years ago I was having a drink in the bar and I saw an old friend who happens to be an attorney here. His name is Bill Harris. He was telling me about developing the O Street market. He said they had an EDA grant, but needed another million-five. He said, 'Do you have any ideas?' I said, 'Yes--and are you willing to pay me a point if I find it for you?' He said, 'Yes,' and we shook hands.

So Monday I called my classmate and fraternity brother from Morehouse, Alonzo Whitfield, who's vice president of Prudential in charge of social investments, and I told him about the O Street market, the first major market in the riot corridor. In two weeks, the loan was made." Models and Money

This year there were two fashion shows benefiting the caucus internship program, one at midnight on Friday (costing $35 per ticket), the other at noon on Saturday (costing $45). Many questioned whether they set the right tone for the weekend, but in the end, when the money is counted, nobody argues. This year's net was expected to be $50,000.

"I was the one who always said, 'A $45 luncheon? That's obscene,' " said Roscoe Dellums, wife of Rep. Ronald Dellums (D-Calif.). "Then I come and I love it. The purpose is to attract people and make money. And this does it."

That's because the show is spectacular. Strutting in time to throbbing disco music and flashing lights, this year's mostly black models wore clothes by Adolfo, Bill Blass, Perry Ellis, Mary McFadden, Mollie Parnis, Anne Klein and Giorgio Armani. "Fantastic," said Nesta Bernard, director of alumni affairs at Howard University. "Dazzling," said Anita Hall, a Bethesda interior designer.

But it was the large array of male models, many of them familiar faces from Gentlemen's Quarterly, who made the biggest hit. When they first walked out on stage, slowly and coolly, a good thousand women erupted in squeals. "Well," said one woman, "the girls don't have to come back."

At one point, three men walked onto the stage in fur stoles that were wrapped around them, loincloth fashion. They had nothing else on but body oil. Joined by three women in full fur coats, the men walked down the runway, their pectoral muscles flexing in time to the music.

After all the furs, leathers, silks, boots, feathers and dazzling gowns had slunk out to the runway and back, the crowd cheered and applauded. And then the models cheered and applauded the crowd.

"I love it, I love it," Renauld White, one of the male models, said afterward. "We never hear cheers like that. There won't be any other point in the year when I'll see, as a group, so many collectively beautiful black people. They're all the ones who've been following my career." 'Political Cowardice'

After Chisholm's speech, Saturday night dissolved into a round of 18 different suite parties. D.C. Del. Walter Fauntroy, chairman of the caucus, had one in the Hilton's Crystal Ballroom, D.C. Mayor Marion Barry had one next door, and Reps. Dixon and Louis Stokes (D-Ohio) had one in the presidential suite on the 10th floor, still going strong at 2 a.m.

It took until noon yesterday for many of the bleary-eyed to surface at Holman's annual brunch, this year held at the Law House in southwest Washington. So before the bulk of the crowd arrived, Holman took time to assess blacks, Democrats and Ronald Reagan.

"It's hard to separate out whether what's happening to blacks is because of Reagan or because of the worldwide and national recession," he said. "While I don't believe Mr. Reagan personally has great animus toward blacks, the important thing is that his basic beliefs and policies operate to hurt poor people." As for the Democrats who are swinging more toward center: "It's pure political cowardice," Holman said. "They're afraid that Mr. Reagan might just be a little too popular. But Democrats have tended to take blacks for granted long before Reagan came along. It seems to me we need to get some new allies. So what I'm looking at is trying to get some of the women's group people, the elderly . . ."

But for a more immediate remedy, Mayor Barry offered one. At his Saturday night party, he took the microphone and told the crowd:

"Those of you who have a drink, put it in your left hand, and with your right hand, take the person's next to you. And hold on to them. For strength, for love, for togetherness. Hold on to somebody. Because you're going to need it."