Tomorrow, the adjectives will run like water - "opening" day for an "interstate" subway of "visionary" conception that will be a "cohesive" force in Washington.

Well, not to rain on the party before it starts, but tomorrow is also the day Georgetown gets left behind forever.

The subway, you see, doesn't stop in Georgetown, even though it passes within one block. It doesn't stop near Georgetown, either. And it will never stip in or near Georgetown.

So the land of begonias and bistros and brick becomes Metro's first orphan community. If that seems puzzling, it seems more puzzling that Georgetown's orphanhood was brought about by Georgetown residents.

It would be hard to fault their motives. They didn't want the streets in shreds for five years. They didn't want the noise or the dust. They didn't want some space-age entryway built beside an 18th-century town house. And they didn't want the exploding shopping centers and apartment houses that Metro will surely bring elsewhere.

But it was 15 years ago that Georgetowners didn't want those things, a time when gas was affordable and parking did not demand quite so much imagination. Now, the people who live in Georgetown, and those who go there to spend money, will be without a choice at precisely the time they need one.

Still, tears are hard to find among the great old oaks. The Georgetown community leaders who took part in the 1962 decision to bend aside the Metro line that crosses from Rosslyn to Foggy Bottom do not regret their decision.

"A line through Georgetown would lead to nowhere but deficits," said a position paper drawn up at the time by the Citizens Associations of Georgetown.

Its longtime vice president, Eva Hinton, read those stirring words to a visitor the other day as she sat in the 34th Street home she has owned for 44 years. "What it means," said Mrs. Hinton, by way of translation, "is leave us the hell alone.

"You come to a point in your life when you've got soemthing," said Mrs. Hinton, who's got a house that has been declared a national historial monument. "If you want to keep it, you've got to do something to keep it." In her case, that something was to staff the barricades against Metro.

The chief concern in 1962, Mrs. Hinton recalled, was the extra-hard rock on which Georgetown sits. To burrow a subway into it would have required extensive blasting. The foundations of many gingerbready Georgetown homes might not have survived.

Mrs. Hinton and her association also wanted to avoid packing Georgetown's commercial strips more than they are packed now. "If you think we need another single souls here at lunch hour or on Saturday, you are mistaken," she said.

Although Georgetown is already a disaster area for motorists, Mrs. Hinton and several Wisconsin Avenue businessmen said a kind of natural selection takes place - just about the right numbers of people arrive, either by car, by bus, or on foot. The car hassle keeps the balance about right, the theory has it.

"The whole charm of this place is that there aren't great surges of people, the way you have in New York, along Fifth Avenue," said one merchant. "Maybe it looks like I'm against progress, but it wouldn't be progress. It would just be the end of Georgetown as we know it."

For many Georgetowners, the nearest Metro stop, at 23rd and I Streets in Foggy Bottom, as much as a mile away, is plenty near enough. "It would be easy to walk there," pointed out Capt. peter Belin, another Georgetown civic leader, "and in case you've forgotten, walking around Georgetown is kind of fun."

The other argument advanced by longtime residents is that a subway would be a redundant commuting tool for them if they work downtown or on Capitol Hill. Georgetown is honeycombed with bus routes that go crosstown, and has been for years. They are popular, and they wouldn't be popular if they wren't at least somewhat efficient.

What of the fact that Metro could carry Georgetowners to National Airport five minutes faster and $3.50 cheaper than cabs? "It wouldn't work," said Mrs. Hinton. "What would I do with my luggage?" And what if she suddenly got an itch to go to he downtown Woodie's, where Metro stops in the basement? "I'd take he bus."

It wasn't just Georgetowners who couldn't see the wisdom of Metro in the early sixties. According to Charles H. Conrad, executive director of the National Capital Planning Commission, only one staff study ever included a Georgetown stop, and it bit the dust early.

"A subway would have wrecked Georgetown," said Conrad. "It was not so much a transit decision as a historic and land use decision."

Veteran Metro staffers report that a Georgetown stop was rejected by them equally early. Not only were the buildings frail, but tunneling would have been staggeringly expensive, and the River Road corridor would not have fed as many suburban customers into a key Northwest Washington line as the Rockville Pike corridor that was chosen.

There was also considerable doubt about whether a subway would have been legal. An act of Congress designates Georgetown a historic preserve, and provides that all new buildings must blend architecturally with those already there.

Nor is Georgetown's nondesire for a subway unprecedented.

Objections from residents of a single neighborhood got the Stadium-Armory entranceway moved. The exact fashion in which the unfinished Shady Grove line will cross from Connecticut to Wisconsin Avenue was changed into less than six times.

Actually, a tip of the cap is due Metro for paying such careful attention to community will. It would be offensive to have subway - and subway construction - shoved down the throat of a community. At least, for a change, the boys with the money and the power listened.

But what has Georgetown done to itself? Have business and citizen groups perhaps been penny wise and pound foolish?

The long and the short of it is that no Metro in Georgetown will mean more cars in Georgetown. That may, in turn, cause economic and environmental damage. And nobody at either Metro Center orWisconsin and M ever intended that.