Sen. William Proxmire served his Fleece of the Month Award for ridiculous federal waste yesterday to the National Endowment for the Humanities for funding an Arlington study on "why people are rude, ill-mannered, cheat and lie on the local tennis courts.

"While there may be too much anger and not enough love on the Arlington tennis courts, spending $2,500 of U.S. funds for this project is a backhanded shot that any self-respecting linesman would call 'out,' "Proxmire said.

The National Endowment ducked, stating that it not only did not see where the shot landed but did not even know a match was being played.

Officials in Arlington7, plagued like other jurisdictions by a shortage of tennis courts, were willing to call the senator's serve a fault and one participant in the study called it a "cheap shot."

William Hughes, Arlington's director of environmental affairs who is responsible for recreation, said, "I think maybe the staff will take enough offense at this to ask the public to refer all their problems to the senator. I'll guarantee you there are many, many complaints about tennis behavior."

Proxmire, chairman of the Senate Banking, Housing and Urban Affairs Committee, is a renowned jogger who once jested that he gave up tennis after he began losing to his wife. "By watching Ilie Nastaser or Bob Hewitt throw their tantrums on national television taxpayers could be saved the expense," he said.

"The taxpayers of this country have been aced for some pretty stupid projects," said Proxmire, "but a grant to study tennis court etiquette is the biggest default to date.

"The ball is in your court, National Endowment. Studying why tennis buffs hog the courts is not exactly on any list of national spending priorities of which I am aware," said the Wisconsin Democrat.

At the National Endowment, public information officer Darrel Dechaby issued a statement that the Endowment "did not in fact make the grant referred to by Sen. Proxmire."

Dechaby said the National Endowment had provided $377,000 to the Virginia Foundation for the Humanities and Public Poley, which it s required by federal law to fund.

That money is "regranted within the state by the completely autono mous committee without further reference to the National Endowment," dechaby said.

Robert Vaugh, director of the Virginia foundation, said. "We funded this program on legitimate grounds and we still think it was legitimate."

Vaughn said the Fleece award appeared to be based on "a distorion or misrepresentation of the purpose" of the study.

The grant was approved by a 17-member state board that includes Edgar Shannon, former President of the University of Virginia, State Del. Dorothy S. McDiarmid from Fairfax County and Arthur Arundel, owner of the weekly newspapers in Loudoun. Faquier and Rappahannock counties among other enterprises.

"It is a very diligent board, very conservative with their money," Vaughn said.

The idea for the study came from Helen Sweeney, director of Arlington's Williamsburg recreation district, one of six in the county.

"It all started because I have an advisory council and we were looking at problems that plague the area. There are not enough tennis courts and the county policy on priority for Arlington residents and an hour of playing time is unenforceable," said the 40-year-old Sweeney, who has been with the recreation department for 13 years.

"Everybody nationally is having trouble with the tennis court situation and it's uncomfortable to wait four hours for a court," she said. "I called a 'tennis town meeting' last September and I discovered that citizens understand the fiscal crisis and that there is no money to build more courts. But they were willing to try to monitor the courts themselves.

"I thought that was fascinating and an opportunity to study citizen participation in policy making and enforcement," Sweeney said.

Sweeney got a $2,500 grant to hire Dr. Tom Wyatt, a sociology professor at George Mason University, and Dr. David Little, an ethics professor at the University of Virginia, as consultants and to draft questionnaires and hold two public meetings.

Unfortunately, the first meeting was set for the night of President Carter's energy message and the second view, so the turnouts were small, with about 25 or 30 participants each night, she said.

"Now it's gotten into a gigantic issue," Sweeney said , "I talked to an side from Proxmire's office last week but he didn't suggest I was going to win any Golden Fleece Award. I'm perplexed but enjoying it.

Little, who described his own role as "a little marginal," said, "Basically the study wasn't to find out why people were rude. The exercise was to involve people in solving a common problem, to see if citizens could contribute to solving a serious local problem."

And Sweeney, who said she had spent only $1,800 of the grant and would be returning the rest, said, "I called Sen. Proxmire's office after I heard about the award on the radio. They read me the statement and I thought it was clever and a marvelous play on words. But they didn't understand the grant. I hope it will call attention to the problems on tennis courts."