The Supreme Court, trying to clarify its definition of obscenity, said yesterday that state antipornography bans on "lust" may go too far in barring materials that merely "arouse normal sexual responses."

But the court, in a 6-to-2 decision written by Justice Byron R. White, said that a federal appeals court exceeded its authority when it struck down all, rather than part, of a Washington state law aimed at "moral nuisances." The case brought the court back to the recurring problem of distinguishing movies, books and magazines that are obscene -- and therefore not protected by the First Amendment -- from those that are not obscene and therefore protected.

The Washington law, which took effect in 1982, defined obscenity as material that "incites lasciviousness or lust." The 9th U.S. Circuit Court of Appeals struck down the law, saying it went too far in including "lust." The appeals court cited a famous 1976 Playboy interview with then-presidential candidate Jimmy Carter and said Carter "confessed . . . that he had 'looked on a lot of women with lust.' "

Carter was not describing a "shameful or morbid interest," the appeals court said. "Rather, he was obviously expressing a healthy, wholesome human reaction common to millions of well-adjusted persons."

The appeals court, White said yesterday, did not believe that the Supreme Court "intended to characterize as obscene material that provoked only normal, healthy sexual desires." The Supreme Court does "not differ with that view," White said.

The high court, which last overhauled obscenity laws 12 years ago, did not intend to "characterize as obscene . . . any and all speech that aroused any sexual responses," White said.

In 1973 the court said that something is obscene if it appeals to "the prurient interest," describes sexual conduct in a "patently offensive" way, and lacks serious literary, artistic, political or scientific value.