Sally Cameron, a Smith College graduate who speaks French and Arabic, went back to school a few years ago and emerged from Yale University in 1980 with a master's degree in public and private management. She figured the additional education would help her advance in a business career.

Cameron's first job after Yale, however, was as a waitress and bartender in a Latino tavern. She currently works nights as a proofreader for a Washington law firm, where she will be laid off Dec. 15. So far, her job options include research work for a former professor, occasional stints as a housekeeper/companion to a widow with emphysema, and perhaps a position as a messenger.

"In the last two years I've had less challenging jobs than before I went to graduate school," says Cameron, 31, who hasn't been able to land a position even remotely suited to her skills and training. "It's frustrating."

To pay their bills and survive, Cameron and thousands like her have joined the ranks of the "underemployed" -- those people forced by the tough job market to take part-time or full-time work for which they are overqualified and unenthusiastic.

Washington these days is a particularly difficult place to match an impressive resume with a challenging job, and the underemployed turn up in almost every office and profession, according to agencies and employes. Lawyers are working as paralegals; auto workers are now supermarket baggers; professors are driving for rental car companies; RIFfed government managers are waiting tables; and graduates who speak Chinese are working as newspaper copy aides.

Because it's the capital, Washington has always been a magnet for young people ready to start at the bottom and work up. The problem now, according to employment experts, is that college graduates of all ages are ending up in jobs that aren't leading anywhere.

The underemployed readily concede that having a low-status, low-paying or unchallenging job is better than having no job at all, especially with the economy the way it is. Still, it can be a jarring, even humiliating, experience to study and train for one kind of work and wind up in a job not nearly as interesting as the career once planned.

"People are nice here and they understand this is not the job of my dreams," says Mel Rodenstein, a recently returned Peace Corps volunteer who, with a master's degree in public and international affairs, now works as a file clerk at the World Bank.

"It's so mindless . . . a 10-year-old could probably do it," Rodenstein, 32, complains. He earns $4.25 an hour, $170 a week, "transferring sets of files from old folders to new folders" and admits he can't help thinking, "Gee, I'm better than this."

There are no precise records on the various aspects of underemployment. But the Bureau of Labor Statistics reports that the number of persons employed part time who want to work full time has climbed from 4.3 million in July 1981, considered the start of the recession, to 6.5 million as of October 1982. And area employment agencies say they see the problem -- and what one placement official describes as "job-hunting desperation" -- every day.

"I'm finding more talent than I've ever seen in 15 years in this business," says Ann Mead, who owns Job Bank Ltd. in Alexandria. "A woman was just in here who had almost a PhD in several esoteric areas, and she was interviewing for a messenger job for the government."

The woman won't get the job, Mead added, because there are other applicants with previous messenger experience who are better qualified for such a post "and are not going to leave it."

"It's a buyer's market right now," confirms Doe Symes, who manages the Virginia office of Career Temporaries, International. "There are so many highly qualified people with excellent skills, and almost everyone who comes in the door says, 'I don't care what it is, I need cash in my pocket.' " She notes with concern -- and surprise -- that laid-off workers seem to have a particularly difficult time finding a new job because few employers want to hire them.

"It used to be that years ago it was highly desirable to have a college degree," says Rosine Gothard, a branch manager for Career Blazers. "But today, since so many have degrees, companies also want to hire someone with experience."

"Economic conditions are now affecting professionals," says Abbie Thorner, director of career planning and placement at Georgetown University Law Center. Even lawyers, she says, are finding that Washington is no longer the "boom town" it was in the '70s, especially in regulatory fields such as energy and civil rights. Still, she adds, the poor economy has meant that "bankruptcy and divorce lawyers are thriving."

Sar Levitan, professor of economics at George Washington University and former chairman of the National Commission for Employment and Unemployment, says high unemployment has enabled employers to hold out for more highly educated applicants. But he worries that too many people are being forced to get degrees to vie for jobs that don't really require a college education or graduate schooling.

"We have almost one million BAs, 300,000 master's degrees and 30,000 PhDs graduating every year," he says. "Can the economy really use that many?" He warns that having "a surfeit of any commodity -- a BA or an MA -- means that eventually it will stop paying off."

The glut of job hunters with degrees is viewed another way by John Touchstone, director of economic resources for the Metropolitan Washington Council of Goverments. He attributes underemployment to "what seems to be a mismatch between the kinds of jobs available and the kinds of jobs we're losing." The person with the liberal arts degree usually can't take advantage of the jobs opening up in the computer industry, he says.

Maureen Golden, director of career services for Johns Hopkins University's School of Advanced International Studies, says the tight job market also has meant that people with jobs stay in them longer, thus tying up traditional entry-level jobs that normally would become available.

Whatever the reasons for underemployment, those who find themselves in that situation can become dispirited quickly. They may be paying their bills, just barely, but it means tending bar or joining the typing pool when they would rather teach or join management.

"I really feel that if I do this for too long I'm going to become stagnant," says Susanne Baldwin, 36, who works three to four nights a week as a bartender.

A college graduate with a degree in European studies, she taught high school seniors in Florida for 5 1/2 years before moving to Washington and doing public relations work for a private foundation. She left the foundation in 1980, expecting to find more challenging work at a trade association.

"But my timing was really off -- the first place where they were laying people off was trade associations," Baldwin says. She continues to job-hunt among trade associations here but finds it tough competing with RIFfed and other college-educated applicants who are "all out there with their little degrees, too."

Noting that "tips are not as high as I was promised they'd be when I was on the other side of the bar," she says she may have to leave Washington to support herself.

Fred Kardell, 29, has six years of schooling at the New England Conservatory of Music in Boston and the Peabody Conservatory of Music in Baltimore. He plays the violin. He also works 8 a.m. to 4:30 p.m. as a mail clerk at the Department of Energy.

"It's tedious, just the same thing day after day, and I feel that my mind and knowledge are just going to waste down here," Kardell says. He expects to graduate from George Washington University some day but can only afford to take one class at a time. He describes himself as "desperately job-hunting."

But until they land better jobs, the underemployed say they are trying to make the best of it. They are also trying to economize.

"I've learned creative new ways of using beans and rice, and I'm cutting out store coupons," says Rodenstein, who credits his Peace Corps volunteer days in Costa Rica with showing him how to live cheaply.

Cameron says the night work has left her days free to become an active volunteer with the D.C. Crisis Hotline, where she is a board member. Baldwin has written two novels and learned a lot about mixing drinks.

"But if I had it to do over again, I would be more career oriented," she says, noting that she went to college "for the learning . . . .I don't think anybody who went to college when I did ever dreamed they'd have to take a job just to pay the rent."