Ariel Sharon conceded in court today that for much of his military and political career he has been dogged by allegations that he had been involved in a 1953 massacre of Palestinians.

The former Israeli defense minister also acknowledged that he had been reviled on picket signs as a "monster" and "minister of death" by Israeli demonstrators in the fall of 1982 after Lebanese Christian Phalangist militiamen entered two Beirut refugee camps and massacred more than 700 Palestinians.

Asked by lawyer Thomas D. Barr, representing Time magazine, if those charges and epithets had hurt his reputation, Sharon responded by shouting, "My answer will be 'I don't know . . . .' "

In his sixth day of testimony in his $50 million libel suit against Time Inc., Sharon said that he had complained after a formal Israeli commission found him guilty of "indirect responsibility" for the killings by the Phalangists. Sharon conceded that he had said the report by the so-called Kahan Commission had stamped him with the "mark of Cain."

The questions about Sharon's reputation seem designed by Barr to buttress Time's defense that a February 1983 article did not hurt Sharon because his reputation was already so low.

The Time article asserted that a secret appendix to the Kahan Commission report contained details of a conversation Sharon had with Phalangist leaders in Lebanon the day before the Beirut massacres began. Sharon allegedly discussed the need to "take revenge" for the assassination of Phalangist militia leader Bashir Gemayel.

Sharon argues that the article unmistakably implies that he had instigated the killings and that this allegation has seriously harmed him. Both these assertions are among the thorny issues in this case. Sharon's lawyer, Milton S. Gould, had said Sharon is not claiming that the Time article cost him loss of earnings or a job, although Sharon lost his post as defense mininster on the Kahan Commission's recommendation.

Gould has said that Sharon is fighting for an accurate accounting of his role in history books. The $50 million he seeks in damages is primarily for punishing Time to make sure it does not behave the same way in the future, Gould has said.

Time has argued that Sharon's reputation has long been one of a "bloodthirsty, insubordinate militarist." Today, Time got Gould to agree that as Sharon ascended in the Israeli military and in politics, the press carried reports that he had led a 1953 raid in which many West Bank Palestinians were killed.

Time's lawyers also argue that the February 1983 article did not accuse Sharon of inspiring the Beirut massacres.

In private conference this morning, Judge Abraham D. Sofaer said he believes that the sparring between Time and Sharon over the article's nuances "could confuse the hell [out] of the jury, not to speak of the lawyers and the judge."

In the conference, the judge gave the lawyers copies of a 15-page draft opinion detailing how he will instruct the jury to consider the two sides' arguments. He forbade the lawyers from discussing or distributing the draft opinion.

Meanwhile, in a related matter, Barr said Time's lawyers in Israel have reported that the Israeli Supreme Court heard arguments today on Time's request to subpoena testimony of several top-ranking Israeli military officers in their companion efforts to gain access to the secret appendix to the Kahan Commission's report.

Previously, the Israeli attorney general had ruled that testimony by the officers and Time's examination of the secret appendix could endanger Israel's national security, and he blocked both requests. Time has accused the Israeli government of acting in collusion with Sharon to deny access to critical evidence in the case.

Barr said the Israeli Supreme Court is expected to rule Tuesday on the magazine's appeal of the attorney general's order.