THE OUTRAGES of which the North Korean government is capable continually outstrip the imagination of civilized people. Just a few weeks ago, for instance, a reasonably calm discussion was under way in international circles over the terms on which this grim Communist state might compete in next summer's Olympics in Seoul and possibly even host a few of the events. Everyone knew the North Koreans have a long record of terrorist atrocities, but it was being said that the prospect of condemnation and isolation at a moment when rival South Korea was reaping a harvest of international prestige and good will would keep the North on its good behavior, at least for a while. Pyongyang, after all, had been putting out a few feelers and otherwise demonstrating a tentative new openness to the outside world. Perhaps this is why there was no great swell of suspicion and protest when a South Korean airliner was bombed out of the sky off Burma on Nov. 29 with the loss of 115 lives. There is also, unfortunately, a certain fatigue factor in international opinion: the acts of repeat perpetrators become taken as routine.

It comes as a harsh but necessary return to reality to read of the follow-up to the Nov. 29 bombing. A 26-year-old North Korean woman aboard the first leg of the fatal flight has told authorities in Seoul that she and a male companion, working under orders from the son and heir apparent of North Korea's leader, Kim Il Sung, placed the bomb. When arrested, the two swallowed cyanide; the man died, but she survived to tell the tale. Her report that she was trained for two years to pass as a Japanese by a Japanese woman who had been kidnaped from a beach has led police in Tokyo to reopen the cases of three young women who disappeared mysteriously from beaches 10 years ago.

After interviewing the woman and obtaining ''independent confirmation'' of her account, the United States has put North Korea on its list of countries practicing international terrorism, and has cancelled its gesture of last March of making American diplomats available for talks with Korean diplomats. So Pyongyang is back in the American deep freeze, and the thin premise of respectability it was trying to convert into participation in the Olympics is in tatters. How do its patrons in Moscow and Beijing feel about their client's unspeakable act?