THE GREEK TYCOON - K-B Cerberus 1, K-B Crystal, K-B Silver, Springfield Mall Cinema 1, Tyson Twin II.

Designed to pander to your lowest appetite - the lust for gossip - "The Greek Tycoon" is not as tasteless as it might have been. But the restraint that it does show is exactly what weakens it dramatically.

Probably there was no way in which a good dramatization could have been made of the marriage of an assassinated President's widow with a greek billionare. This is too bad, because the goings-on of the high and mighty, as a Greek once noted in a book called "Poetics," do make good dramatic material. But as a New York book editor, Jacqueline Onassis, once noted in connection with a book she edited that dwelt on gamy gossip about Russian royalty, there is some difference between using a living celebrity and a dead one. Any historian can tell you how Napolean's mind worked; doing this for Nixon is more risky.

The difference is not so much an ethical one as the New York editor suggested when she found it permissible to gossip about Catherine the Great while deploting people who gossip about herself, but a matter of attitude on the part of the dramatizer and the audience. In dealing with the past, you may fashion a full character, with internal constistency and motivation, who may or may not describe a person in history. A celebrity who is alive, however, already has a simpler public character - what we call his "image" - generally contradicted by contemporary gossip purporting to reflect the "real" person. The biographer must explain the image, while seeming sophisticated enough not to be taken in by it.

"The Greek Tycoon" fails to do either. Coasting on the audience's knowledge of its heroe's lives, it fails to provide them with any motivation at all. A number of popular theories circulated about the Kennedy-Onassis marriage when it took place - that her greed for money matched his for fame, that the two Kennedy assassinations and public instrusions on her had frightened her into seeking protection, that she had a daughterly love for him - and it is certainly possible that none of them had any validity. But people who rejected these explanations and couldn't come up with any others had no business attempting this story.

Jacqueline Bisset is fittingly dignified as the Jacqueline Kennedy character, and Anthony Quinn fittingly vital as the Aristotle Onassis one, but neither characterization adds anything to what a devoted reader of Photoplay or Oggi might already know.

After adandoning any attempt at safety-ing public curiosity about why prominent people behave as they do, the picture's only excuse would be to satisfy curiosity about their luxurious artifacts. Here the film also misses. That Jacqueline Bisset is not as dramatic-looking as Jacqueline Onassis is forgivable, but that the clothes, yacht, villas and art collection are those millionares, not billionares, is unforgivable.