The governing board of Washington's exclusive Cosmos Club is moving to suspend or expel the leader of the movement to admit women to its all-male environs, accusing him of "ungentlemanly behavior" in a list of charges that includes spreading misrepresentations, using "strident language" and "pestering members."

Samuel P. Hayes, a 75-year-old retired economist who is chairman of the committee pressing the women's issue, has been advised that the club's Board of Management will act on the charges Thursday, according to an Aug. 6 letter to Hayes from Cosmos Secretary John B. Farmakides.

The letter, a copy of which was obtained by The Washington Post, accuses Hayes of engaging in a "pattern of offensive behavior" that has annoyed members and "is destructive of the atmosphere the club members are entitled to enjoy."

"Rubbish," sputtered one Cosmos member when told of the charges. "Sam Hayes is a gentleman."

Said another: "Pestering members? They must be kidding."

The move seemed certain to ignite passions on both sides of the battle over women's membership that has raged for more than a decade behind the ornate doors of the club's Embassy Row mansion at 2121 Massachusetts Ave. NW. Four times since 1971, members have rejected proposals to admit women to the elite club that was founded 107 years ago for "men of accomplishment."

Because the Cosmos Club is not tax exempt, it is under no legal obligation to admit women.

But the issue at the club, where members meet and dine in an atmosphere of scholarly gentility, just won't go away.

The controversy raged anew last May when officers announced a new policy requiring that prospective members sign an oath stating that they will not work actively to change the bylaws excluding women.

This month, however, in the bulletin that goes to more than 3,100 members, the board announced that it was dropping the new rule. "To a large number of members -- including members firmly in favor of the present membership policy -- the requirement appeared intended to stifle discussion and dissent among all members, new and old," the board announced in the bulletin. "Such was not the board's position. The statement compelled no loyalty oath."

However, the board left intact another new requirement that new members sign a statement confirming they are aware that the club does not admit women and that they are not "embarrassed in any way" by the policy. Also left intact, according to several members, was a new policy to interview prospective members.

A club member, who favors the admission of women, scoffed at the board's action. "This alleged concession is no concession at all. They've retained the essense of the new rule, which is having people interviewed," he said, adding that the only reason for an interview is to check a prospective member's view on the single-sex issue.

Club President George E. Hartman did not return numerous telephone calls to his office yesterday, and other club officers referred all questions to him. "Only the president is authorized to speak," said former president Floyd M. Riddick, refusing to discuss the issues. "I don't want to get kicked out."

Indeed, encouraging statements to the press -- an act the board refers to as "reprehensible" in its letter to Hayes -- is one of the charges against him. Club bylaws prohibit statements by anyone but the president about club policy for publication in the media.

Hayes, in his written response to the charges, denies ever releasing any information to the press. "The Board can offer no evidence to the contrary and should in good conscience withdraw this charge," his letter states.

The board also has accused Hayes of misrepresenting facts about the club's membership and financial stability in communications to club members, using "strident language" designed to command attention and "pestering members" for several years about changing the bylaws.

"The Board believes that it is boorish and ungentlemanly to pester Club members continuously about your favorite issue, no matter how noble you may believe the cause to be," the board's letter states.

To that, another club proponent of admitting women, said: "Pestering is a value judgment by the group which does not like what is being said. Sam Hayes has been advocating . . . . It just makes them look silly. I regret the club leadership would hold us up to public ridicule just to punish someone who has a different view."

For his part, Hayes, in his letter to the board denying the allegations, charged that he has been singled out for actions "on behalf of, and with the approval of, a significant group of Club members." The Committee of Concerned Members of the Cosmos Club, the group he heads that is pressing the women's issue, claimed more than 450 supporters as of last June.

"Contrary to Mr. Farmakides' assertion that the Board's charges relate only to my 'behavior,' and not to my views, it seems obvious that the Board has brought charges against me because of my views," Hayes states in his letter. Later, he writes, "The Board will understand my distress that I, like the 'scapegoat' of pagan rituals, should be held personally accountable for all that the Board finds distasteful."

Hayes, a Cosmos member since 1948, told a reporter he could not "talk about club matters," but when pressed on whether he considered himself a pest, he suggested, "Well, if you talk to some of the board members, ask them what the evidence is."

Another member, who also asked to remain anonymous, worried that the board's action against Hayes, "has the seeds of destruction of the institution. If an institution like the Cosmos Club cannot have civilized debate among its members, what club can?"