"Proper?" said Margaret, the duchess of Argyll, a remarkable presence of poppy-red chiffon and elegance. "Well, I don't misbehave in public."

And in private? she was asked.

She threw back her head and let out a deep, wicked but engaging laugh.

Margaret, the duchess--who retained her married title although the duke divorced her in 1963 in what amounted to long, scandalous proceedings that rocked Scotland--came to Washington yesterday from London after a stop at the America's Cup races. She was a portrait of diamonds and dignity--not at all like you'd expect of someone who garnered sensational headlines when the duke sued her for divorce, charging adultery with a string of men.

"Oh, yes, I do have regrets in my life, but I would probably do it all again," she said in a lofty accent and the knowing tone of a woman who has seen it all. She said her life was probably "too exciting" and demurred coquettishly on her age. But finally offered: "Just put 'in her sixties,' if you would be so kind."

The woman she most admires is Margaret Thatcher. She declined to comment on men. "Not movie stars," she said. "They're too conceited . . . I better stay away from naming the men . . . You know . . ."

Her host for the typically Washington dress-up affair at the Embassy Row Hotel was Steve Martindale, the lawyer who is also a professional Washington guest and a party giver of a decade past. The guest list was noteworthy: Attorney General William French Smith and Jean Smith, Charles and Mary Jane Wick, Senate Majority Whip Ted Stevens (R-Alaska), Chief of Protocol Selwa Roosevelt, Swedish Ambassador Wilhelm Wachtmeister and his wife, Ulla.

"I knew her the duchess in London," said Roosevelt. "No, I don't remember much about the divorce."

Not many last night did. Of course.

There was a press release about the party that listed the guests, described the "burgundy moire cloths and contrasting white chairs" and explained the duchess' itinerary while in the states.

Martindale, never shy about cameras and ink, announced a change of heart at first.

"What! A press release! I didn't know anything about it," said Martindale, who maintained it was not his doing. "Margaret would just kill me if she knew. Who did it? I'm livid. My guests will think I'm exploiting them."

Anyway, that didn't last long. He posed for all the pictures. Everyone called everyone else "dear" and "darling," and double-cheek kissing was the norm for the night. Kissing the air was popular so as not to leave lipstick stains.

Martindale said he met the duchess 10 years ago, and no, no, no, all those appalling things written about her couldn't be true.

"No, no, she's the most proper woman you ever met in your life," said Martindale. "My theory about that is that she was ahead of women's liberation, and that she took a beating . . . and went before judges that were owned by the duke of Argyll."

"I hate women's liberation," noted the duchess, when asked if perhaps she was a victim of a man's world. "I want to be the frail woman always cared for. I don't want any rights. I don't want to fight for anything. I'm tired of all these women screaming. I prefer to work in a quite gentle way, behind the scenes."

The trial was seamy. Wonderful material for a soap with a collection of diaries, photos, men and the duchess' stepmother--all introduced as evidence. In May 1963, a Scottish judge granted the duke a divorce and described the duchess as a "completely promiscuous woman whose sexual appetite could only be satisfied with a number of men." The verdict then went on to list the men with whom the court believed the duchess had been intimately involved.

Before all that, however, there were better times. The daughter of a Scottish businessman, Margaret Whigham was first married to American golfer Charles Sweeny. Cole Porter mentioned her in his song "You're the Top," Elizabeth Arden designed a special lipstick for her, and she was very rich.

Then came the duke and the divorce. And there went her money. A few years back she resided in a large home in the Mayfair section of London and charged admission to "visitors"--not to be called tourists--who appreciated the pleasure of tea with her.

"None of it affected my life at all," she said, eyeball to eyeball. "I'm here and I'm quite happy, aren't I? It was all so long ago . . ."