Bobby Knight, an Ugly American even at home in Indian, was at it again Thursday night.

The U.S. basketball coach in the Pan American Games was screaming profanities and insults in the face of the youngest player on his team in a voice so loud that thousands of fans could hear him.

"What the hell's the matter with you? Do you think I'm going to put up with this bull bleep?" belowed the livid Knight, 38, his 6-foot-5 frame bent over 6-1 Isiah (tuss) Thomas, their faces inches apart.

The veins and muscles in Knight's satanically dark face bulged as he bumped and badgered his 18-year-old guard -- not for a few seconds but for minutes as both stood at midcourt. Thomas, his face stunned and blank, stood and took it, as Knight's epithets escalated to the unprintable.

"Loco, loco," muttered the Latin American fans, accustomed to athletic fanaticism, but hardly prepared for the raw, conscienceless villainy of Knight in high dudgeon.

When the first half ended, seconds later, Knight sprinted on court, grabbed Thomas and screamed maniacally in his face all the way to the locker room. He benched him the second half. Knight is the coach at Indiana University, when he is not spereading good with in the Caribbean by getting ejected from a Pan-am game with his team ahead by 35 points. Thomas, Chicago's top high school player in 1979, has enrolled at Indiana.

Welcome to four years of The Edge of Knight.

To call Knight a Jekyll-and-hyde personality would be understatement. It took Jekyll several seconds of gasping and fang-growing to become Hyde. Knight can do it in a flash.

Knight's face is his fortune, and his sorrow. Even in repose, his expression combines intelligence, animal magnetism and potential menace. Other men's faces show less than they feel.Knight's commonly conveys more -- often to his deteriment.

This week Knight's multiple personalities have been on vivid display. He has ranted at his team behind closed doors after they won a scrimmage by 13 points. He has cursed players on the bench publicly and loudly.

Knight not only was thrown out of the gym in a game against the Virgin Islands but was reprimanded by the International Amateur Basketball Federation, lectured for half an hour by Pan am officials and cornered into a tepid apology. "I didn't really apologize," Knight said today. "I just said I wouldn't want to go through it all again."

One federation official called Knight's ejection -- the first for a U.S. coach in Pan Am or Olympic competition -- "a very serious violation," adding that another infraction would get the U.S. expelled from basketball competition.

Thursday night, after the 82-78 victory over top contender Brazil had pushed Knight's team a giant step toward a gold medal, he was in fine form -- analytical, acid, candid, injudicious and occasionally charming.

Those who enjoy hating Bobby Knight from afar are better off if they don't get to know him.

After his nondescript team, one of the least known that the U.S. has fielded internationally, had in successive games beaten its three toughest opponents (Virgin Islands, Cuba and Brazil), Knight blasted his players as immature and lazy.

"We're just a very, very immature club that doesn't know what it means to be mentally ready to play," said Knight. "I'm disappointed . . . from a spectator's point of view, the wrong team won. The hustling team, the tough rebounding team was Brazil, not us.

"For two days, since we beat Cuba, they've been listening to how good they are -- and they played like it. They have to learn that we're not down here to play Rosemary and the Seven Dwarfs."

Of his 7-foot-4 center, Ralph Sampson, the 18-year-old prodigy who laid his opinion on the line.

"Some of those idiots in the pros are saying he's ready for the NBA. And, of course, all the college coaches who know they can't get him go along with that baloney because it puts more pressure on whatever coach does get him. [He's headed for Virginia.]

"Well, Sampson not only isn't ready for the NBA, he isn't even ready for college ball at this point, He'll need all four years. He looks lost on the court against these guys down here. He's not aggressive, he doesn't go after the ball.

"He's used to aying 'boo' to high school kids and they stay away from him. These Brazillians don't know him from a tall ladder. They attack him, beat him up. and he's no factor in the game."

Of all Knight's eruptions here, he saves his best for the critics back home who have relished his ejection and embarrassment. Knight knows that the show of temper had caused the fuss was practically nothing, a mere tiff to which a macho ref who speaks no English overreacted -- judging Knight by his florid face, not his placid words.

"That makes me sick, that just nauseates me," Knight said when told that Joe Garagiola had criticized him on radio show pointing out that U.S. coaches in international competition are supposed to avoid incidents, not cause them.

"Gargiola doesn't know beans. He can stick it in his ear. He can . . ." said Knight, enumerating several impossible acts.

"I don't need all this, I've won everything a college coach can win. I don't have to prove myself. I was asked to take this job and I accepted as a favor," said Knight, scathingly."I had a benefit game in Bloomington (Ind) and raised $50,000 for the Pan Am Games.

"I'm not here to have a good time or to make a trip I don't like this hot weather or no air conditioning or sitting outside the gym in a bus for an hour waiting for the preliminary game to end.

"If i'd wanted to have a good time, i'd have gone fishing.

"Instead, starting May 20 we had six days of trials, then we played in Italy for six days. Then after eight days off, we've been going at it steady since June 12. This is no damn vacation.

"I'll tell you what made me feel good. As soon as I got here, a Puerto Rican friend came up and said, 'Bobby, as soon as I saw you were coming down, I knew the U.S. had decided to play to win.'"

So, there is the Knight conundrum in a nutshell. He is, in one sence, the final product of an American college sports system that takes high school eniors and drills them with the value of one word -- win.

As a player, Knight was a brilliant jump shooter who played lousy defense and rode the bench on the phenomenal Ohio State team that had John Havlicek and Jerry Lucas.

As a coack, it is alwats noted -- as though it were a contradiction -- Knight stresses things like defense, ball handling, rebounding and toughness, the things that were his flaws as a player.

On the contrary, Knight coaches the same way he played. He was a glory-hound then, and remains one.

At every opportunity, Knight takes the game away from his players and tries to control it himself with strategies, pep talks or tirades. It is no mistake that he insists, "this game is 5 to 1 mental over physical."

In a college coaching profession full of enormous egoes who try to express themselves through their players, Knight is perhaps the most insistent on having obedient robots on court.

Ironically, Knight has been castigated here for all the wrong things. His ejection was a picayune incident. It is his almost daily tirades at his players that deserve censure.

These players, average age 20, are not in any sense Knight's players. They tried out for the U.S. team, not Knight's Indiana squad. They are his captive audience.

"These players are all here for one reason," says Knight. "Because they want to make it to the Olympics in '80."

So, they have to put up with Knight's grandstanding abuse, his perpetual spotlight grabbing. Their one break is that the 1980 Olympic coach will not be Knight, but that laidback guy sitting in the Pepin Cestera bleachers here with his feet up on the chair in front -- Dave Gavitt of Providence.

Knight merely is prepping himself for an eventual Olympic spot. That is the reason for his enthusiasm for a dirty job.

There is no question that Knight is fit to be the U.S. Olympic coach. His record proves it -- he can win, just as he probably will win the gold medal here with a raggedy team.

But there are many types of fit coaches, many ways to win, Knight's drill instructor methods have no instrinsic advantage over other approaches. They merely suit his personality.

The reason that Knight, as he presently is constituted, should not represented the United States in the future, is not because he is not fit.

It is because, in the deepest sense, he is not proper.