As a matter of principle, Washington does not generally acknowledge its essential silliness.

But yesterday hogs marched and grown men wore diapers in Georgetown.

The third annual Trumbull and Core Gross National Parade set new standards for the tasteless and the absurd. Bill Trumbull and Chris Core, the WMAL announcers who originated the parade, led it off under "A Tournament of Noses" banner. Hog snouts were much in evidence. The real pigs came later. A sign pleaded: "Please laugh -- it looked funny on paper."

"I think the parade lived up to its name," said Arch Campbell of WRC, one of four parade judges known as the Injustices. "It was gross."

"It just goes to show that under all those drab gray flannel suits beat the hearts of real reprobates," said Jane Coates, a spectator who works at the Library of Congress. "There's a lot of silliness in this town but it's kept behind closed doors. This is the only time we can come out of the closet and be ourselves."

They began at 18th and M streets and made their way through Georgetown. It was not so much a line of march as a straggle. Forget precision and forget propriety. There was neither.

Oh, yes. The Toro, Toro, Toro Precision Lawnmower Drill team performed. "Gentlemen, start your engines!" And the Synchronized Precision Briefcase Drill Team members marched smartly in their power suits, executing impossible maneuvers for those in A-line skirts. At least they were respectable.

Team X won the Foot in Mouth Award for its display of Washington Trivia. Question: "Where is National Airport Gate 85?" Answer: "The USA Today building." Question: "How did Reagan respond to Mitterrand's demand to drop your dollar?" Answer: "Up your franc." Question: "What happened when Nancy Reagan fell down?" Answer: "She broke her hair."

There was only one way to watch the spectacle: from the gutter. "This is my parade position," said Andrew MacKay, a George Washington University student reclining against the curb of " M Street. "I'm a derelict."

The intense April heat shimmering off the pavement added to the sense of the surreal. Adult men flaunted beer bellies that didn't bear scrutiny. Pasty thighs bulged from shorts that still smelled of mothballs.

"I came down here for a date and ended up in the street," said Linda Herman of Baltimore. "It just goes to show what Washington men are all about. Give her a beer and leave her on the street."

She pointed to her date, standing on the opposite side of M Street. "He's across in the shade," she said. "He dumped me on the sunny side."

They stood 10 deep along M Street. Teen-agers clung to windowsills. Children clung to their fathers' shoulders. Parade officials from WMAL said the crowd size was between 80,000 and 100,000, but police issued no official estimates.

Still, the crowd was strangely subdued. "I think everyone is a little afraid because of the crackdown," said Sherry Sproat of Chantilly, nodding towards the D.C. Police, who were the only thing about the parade that resembled regulation. She swore her cooler was filled with wild-cherry soda.

"I think a lot of them are nonplused," Coates said, surveying the well-mannered crowd.

And why not.

There was a Pooper Scooper Brigade -- led by a fictitious Mayor Marion Barry wearing an outhouse -- and a Yuppie Brigade. There were Test-Tube Babies in diapers and Subversive Fruits and Vegetables. There were Tax Flashers with loin cloths over their Bermuda shorts that read: "Lower Taxes."

The Wurst Band in Washington hurled sausages into the crowd. The Gross National Princess showed a little leg -- which proved to be unusually hairy. The Citizen's Right to Bare Arms carried dismembered limbs made of plastic that were painted a deathly gray.

The International Association of Professional Bureaucrats celebrated the cause of public servants everywhere. One "congressman" carried a board of rubber stamps. A representative of the truly needy carried a martini and posed the question "If ketchup is food, what about the olive?" Another carried a sign that said: "If you've seen one nuclear war, you've seen them all."

The entry from the "Arms Race" marched behind a sign that said "the finish line" and dressed like skeletons.

There were Kapital Klowns who came as Reagan's Kabinet and Kloset. The Labor Department came in a maternity dress. The "Da-Fence Department" came in white picket. Karen Sullivan of Burke was hoping to see the Post Office. "They're the biggest clowns around," she said. "But I didn't see them when the clowns came around."

Traditionalists were not completely ignored. There were bands and balloons and children with stomachaches. There was also a good cause. The parade raised $15,000 for the Metropolitan Police Boys and Girls Clubs, according to Lucille Baur, a member of the parade's executive committee.

But for once, high-mindedness was not the order of the day.

"If you think D.C. is stuffy, you ought to come to the Library of Congress," said Coates. "We're wild and crazy librarians. We wear sensible shoes. Next year I want to be in the Library of Congress Pushcart Drill Team. I don't know if there is one, but if there isn't I want to start one. We can chant the LC system."