The slim possibility that a buyer can be found to save The Washington Star diminished further yesterday as two potential rescue organizers said they were discouraged, and Time Inc., the paper's owner, reported no progress in the search for a purchaser.

R. Robert Linowes, former president of the Greater Washington Board of Trade, who said on Monday, that he was trying to save The Star through a partnership of employes and investors, said he was "getting more and more discouraged as the days go on."

Peter B. Hannaford, a California public relations executive with close personal and professional ties to the Reagan administration, said he had talked to "several people who are wealthy" about taking over The Star and "they were intrigued," but "I really don't think anything is going to come of it."

Hannaford, a former partner of White House Deputy Chief of Staff Michael K. Deaver, said he believes that "a lot could be done format-wise to make The Star competitive," but the potential investors he talked to had been scared off by the magnitude of the paper's losses, which Time Inc. officials puts at $20 million a year.

The only faintly hopeful note came from Boston real estate developer Mortimer B. Zuckerman, owner of The Atlantic Monthly. Zuckerman said he is "certainly interested in the publishing business, but I'm not sure The Star is the place to go." He said he would have a "better answer" about his plans by the end of this week -- by which time The Star will have only a week remaining before its scheduled death on Aug. 7.

At Time Inc., which says it has lost $85 million on The Star since buying it from Joe L. Allbritton in 1978, officials said they continue to receive inquiries about the fate of the paper but they declined to identify the callers. They gave no indication that the situation has changed since Time announced last week that it was giving up on The Star.

"It's really a long shot," said Time Inc. spokesman Louis Slovinsky. "We are very concerned about the Star's 1,400 employes, and if we have any good news to announce, we will do it."

In the six days since Time announced it was shutting down The Star, leaving Washington with only one daily paper, several potential groups of rescuers have talked about putting up the money to keep it alive, only to turn away when they contemplated the reality of a long-ailing paper, abandoned by advertisers and losing circulation, and of how much money has been lost already in trying to turn it around. Business executives and labor union leaders such as Glenn Watts, head of the Communications Workers, initially expressed a willingness to contribute to The Star's survival, but nothing has come of it.

Even a group of Star employes, convinced that the peper's demise is now inevitable, petitioned union leaders, who have been working with Linowes on a rescue effort, to abandon it.

Lyle Denniston, the paper's veteran Supreme Court reporter, said about 80 writers and editors had signed his petition asking The Newspaper Guild to forget what he called "this nonsense of recruiting money for a phantom enterprise" and concentrate on ensuring that Time gives full severance pay to the workers.

The petition was presented at the meeting last night, but a motion for the Guild to withdraw from sale negotiations was defeated by about a 2-to-1 margin. Before the vote, Denniston said that "we have one common foe and that is Time Inc."

In another development last night, Raymond G. Dick, local representative for the Washington-Baltimore Newspaper Guild, announced at the meeting that he had learned the terms under which Time Inc. would sell The Star.

He said that "Time will turn the paper over to a purchaser for $1," providing that the buyer assumes:

A $6.6 million mortgage on The Star building.

$1.3 million in accounts payable liability.

$1.5 million in miscellaneous debts.

Time Inc's liability regarding severance pay to Star employes.

The purchaser also would have to have a cash flow to be able to keep the paper running for at least one year, Dick said he had learned from unnamed Time officials.

Later last night, a Time spokesman, Louis Slovinsky, said of Dick's comments: "Time Inc. will not comment on putative terms nor will we reveal with whom we are talking. We just don't think it's a constructive thing to do. But I can say that talks are continuing with various people."

Linowes, union officials and several Washington-area business executives met yesterday with Mayor Marion Barry to discuss The Star rescue effort. The business executives were there not to discuss investing in the paper but to pledge that they would advertise in it if it keeps publishing.

After meeting for more than an hour, the leaders emerged saying they had little hope for a last-minute miracle to save the newspaper. "It was not looked at as being very encouraging," Barry said.

The mayor said he would try to arrange a meeting within the next few days between the various groups interested in keeping The Star alive and officials of Time Inc. The meeting would seek to ascertain more precise figures on how much money Time wants for the newspaper, Barry said, and whether Time would consider extending the Aug. 7 closedown date.

Linowes said he has not yet found a formula to reverse the newspaper's slide, but added that he expected the various groups trying to save the newspaper to join in a common effort.

Earlier, City Council Chairman Arrington L. Dixon had suggested that the city might consider giving the newspaper tax breaks to help it survive, as various cities have done with other industries, but Barry said he did not believe government should subsidize newspapers because of First Amendment considerations.