The Supreme Court ruled yesterday that the Constitution bars the death penalty for rape of an adult woman.

The court held 7 to 2 that execution of a Georgia rapist would violate the Eighth Amendment ban on "cruel and unusual punishment" because it is excessive punishment and grossly disproportionate to the crime.

The decision spares five convicts on death row in Georgia, the only state that allows capital punishment for rape of an adult woman. It also may spare an inmate in Florida, which permits the death penalty for an adult who rapes a child. The court did not address the Florida case.

The justices could not muster a majority for a single opinion, while the two dissenters united in a strong attack on the ruling.

Justice Byron R. White wrote the principal opinion, joined by Justices Potter Stewart, Harry A. Blackmun and John Paul Stevens.

"Rape is without doubt deserving of serious punishment," White said for the plurality. But, he said, "in terms of moral depravity and of the injury to the person and to the public, it does involve the unjustified taking of human life." He continued:

"Although it may be accompanied by another crime, rape by definition does not include the death or even the serious injury to another person. The murderer kills; the rapist, if no more than that, does not. Life is over for the victim of the murderers; for the rape victim, life may not be nearly so happy as it was, but it is not over and normally is not beyond repair."

Justice Lewis F. Powell Jr., while agreeing that the life of the particular convicted Georgia rapist should be spared, rejected the plurality view that the death penalty is disproportionate retribution for rape.

"The deliberate viciousness of the rapist may be greater than that of the murderer," Powell wrote. "Rape is never an act committed accidentally. Rarely can it be said to be unpremeditated. There also is wide variation in the effect on the victim . . . Some victims are so grievously injured physically or psychologically that life is beyond repair."

Justices William J. Brennan Jr. and Thurgood Marshall reiterated their view that the Eighth Amendment ban on cruel and unusual punishment always rules out capital punishment.

In the dissenting opinion, Chief Justice Warren E. Burger, joined by Justice William H. Rehnquist, found one "clear implication" of the decision: " . . . the death penalty may be properly imposed only as to crimes resulting in death of the victim."

The holding thus "casts serious doubt upon constitutional validity of statutes imposing the death penalty for a variety of conduct which, though dangerous, may not necessarily result in any immediate death, e.g., treason, airplane hijacking, and kidnaping," Burger contended.

The court recessed until Oct. 3 after announcing the death penalty decision and an antitrust ruling.

The NAACP Legal Defense Fund has been litigating for 14 years to strike down the death penalty for rape. Assistant counsel David E. Kendall, recalling that 90 per cent of the 455 persons executed for rape since 1930 have been blacks, said the decision closes "one of the more shameful and racist chapters in the history" of American criminal justice. The American Civil Liberties Union, an ally, agreed.

Women's groups have denounced capital punishment for rape "as a vestiage of an ancient patriarchal view of women as the property of men, as a reflection of societal ambivalence toward the woman victim, and as a barrier to proper and vigorous enforcement of rape laws."

The decision involved Ehrlich Anthony Coker, 26, a white man who raped and then killed a woman in December, 1971; and kidnaped, raped, beat and left for dead a second woman eight months later. Three separate courts sentenced him to three life terms, two 20-year terms and one eight-year term.

He escaped a prison at Waycross, Ga., on Sept. 2, 1974, entered a couple's home nearby, tied up the husband, threatened the wife - who was 16 and a new mother - with a knife, raped her, stole the husband's money and abducted the wife in the family car. He was quickly caught.

A jury found the circumstances - the prior convictions and rape committed during an armed robbery - so aggravating as to warrant the death penalty.

Justice White wrote that the circumstances didn't alter the controlling fact: the rape did not involve "the taking of life." And, he said, Coker was given a separate life sentence for the robbery.

Burger protested that the ruling bars Georgia from shielding its citizens from "habitual" rapists such as Coker. The Constitution did not bar the death penalty for Coker, he said.