Shouting "Scabs go home!" an estimated 2,000 members of Washington area unions taunted and jeered fans entering RFK Stadium, joining striking football players to protest yesterday's game between replacement teams of Redskins and St. Louis Cardinals.

D.C. police reported five arrests for disorderly conduct during the demonstration in the 14-day-old strike, which pitted fans on opposite sides of the labor issue in often vigorous, nose-to-nose verbal confrontations.

However, no serious incidents were reported outside, and inside 27,728 fans watched the Redskins win 28-21.

"Scab players, scab fans!" strikers shouted at 20-year-old Scott McCollam, a college student from Springfield, as he made his way to the stadium entrance in Southeast Washington. McCollam stopped and returned the fire with an obscenity.

"I'm totally against unions and what they're doing," McCollam said later. "They're dogging the fans, and we're the ones who are suffering."

Many area union officials had urged their members to take part in the picket line as a show of support for striking Redskins, and to protest what they view as a union-busting effort by National Football League owners that they fear could weaken organized labor in other fields.

Several dozen area unions were represented at RFK yesterday. There were bricklayers, stagehands, machinists, seafarers, teachers, pipe fitters and letter carriers. A pilot from Eastern Airlines wore his captain's uniform, and a group of mine workers rode a bus to RFK from Pennsylvania.

"They're doing the same thing to us that they're doing with the football players," said the Eastern pilot, who asked not to be identified. "It's a scab economy. They think everybody is replaceable."

Some fans joined the pickets. Wayne Flood drove with his wife and two teen-age children from Fredericksburg, Va., turning down a rare chance to get available tickets for the game but hoping to return home with autographs from striking players.

"We're not tempted by this opportunity to see the game in person even though we've been trying to get tickets for years," Flood said.

Another avid fan, David Master Jr. of Alexandria, waved a roll of toilet tissues, saying they were "scab tickets."

At a rally held while the game was in progress, labor leaders told the crowd of unionists that they were pleased with the turnout, and they were cheered when they vowed to continue picketing games until the contract dispute between players and owners is resolved. While management says the dispute centers on free agency, the players union says that this is only one of several issues, including free agency, pensions and severance.

"There are two kinds of people, and unfortunately you saw them both here today," Tom Donahue, secretary-treasurer of the AFL-CIO, told the crowd. "There's the kind that cares, and you're out here. Then there's the kind that doesn't know enough to care, and they're inside {the stadium}. And that's too bad."

Three members of the D.C. Council attended the rally: Democratic Chairman David A. Clarke, Harry L. Thomas (D-Ward 5) and Wilhelmina J. Rolark (D-Ward 8). Clarke later said he had investigated the possibility of closing RFK Stadium during the strike but decided not to pursue the idea because city taxpayers would probably be forced to reimburse Redskins owner Jack Kent Cooke for lost revenue.

"People who attend the ball games only prolong the resolution" of the strike, Clarke said. "The Redskins are too much a plus in the community for people to accept second best."

Executives of the AFL-CIO, with which the NFL Players Association is affiliated, last week spread word of the picket plans to hundreds of thousands of members in the Washington region.

Only a few players and other pickets were on hand outside RFK yesterday when buses carrying replacement Redskins and Cardinals rolled up to the stadium. Protesters greeted them with angry jeers and gestures, prompting bemused looks from behind the tinted bus windows.

Despite gusting, cold winds, union workers and their families streamed to the site as game time approached, many carrying hand-lettered signs and banners.

One of the largest contingents of pickets consisted of workers most affected by the job action: stadium vendors, who normally sell beer, hot dogs and other items during the games to earn extra income.

Minor Christian, president of the Food and Beverage Workers Union Local 32, said that about 5 percent of the estimated 450 vendors who would normally have worked yesterday crossed the players' picket line. Christian complained, though, that vendors who stayed away had had their jobs or working conditions threatened by concessions administrators.

Stadium officials at the last minute scrambled to find replacement vendors as well as extra workers to stand near stadium entrances in an effort to ensure that strikers did not attempt to impede fans entering the stadium.

Despite the extra security, the surging crowd of demonstrators forced entering fans to run a gantlet of heckling and obscenities as police, who said they posted no more than their usual contingent of officers at the stadium, hurriedly erected barriers to contain the crowd.

"We've got the real 'Skins, you've got the scabs," was one recurring chant among the pickets. One woman, a D.C. teacher who said she has held Redskins season tickets for 25 years, repeatedly lunged at passing fans with her union sign, shouting, "Go on inside and watch scab football! I'll give you my tickets!"

Meanwhile, a group of nearly 100 people attending the game gathered on an outdoor terrace above the stadium entrace in a counterdemonstration, shouting antiunion epithets and cheering the fans who crossed the picket line.

It was these fans who got the last word when the game was over and the demonstrators had dispersed. The replacement Redskins had beaten the St. Louis Cardinals, and as jubilant crowds poured from the stands to go home, a new chant echoed in RFK's concrete halls: "Stay on strike!"

Staff writer Peter Pae contributed to this report.