For hundreds of thousands of American workers, Christmas 1981 is a time of fear.

Since October, nearly half a million workers have been added to the unemployment rolls with most of the rise accounted for by workers who lost their jobs because of layoffs--many of them permanently. Today more than 9 million are unemployed, the highest number since the waning days of the Great Depression.

And most economists now expect the situation to get worse in the months ahead. Adding credence to these predictions were the Christmas Eve layoff announcements by the nation's major automakers as they attempt to reduce the growing inventory of unsold cars in their dealer showrooms.

But the layoffs are only part of the uncertainty facing the American worker in the months ahead. For millions of other workers who manage to keep their jobs, 1982 is shaping up as a year of less. This is particularly true of union workers who are entering a new three-year round of contract bargaining.

Although the new year is still a week away, union contract patterns already have begun to emerge.

In the nation's meatpacking industry, for example, the United Food and Commercial Workers International Union has reached agreement eight months early on a new contract that essentially freezes all wage and cost-of-living increases through August 1985. That contract, according to union officials, was the product of two years of strategy sessions in an effort to preserve benefits already won at the bargaining table.

In explaining the new contract this week, Lewie Anderson, vice president of the union's meatpacking division, said the step was taken to reduce competitive pressures on the employers.

"Although the meat packing industry as a whole is in sound financial condition, meatpackers under the master agreement contract, with combined wage and fringe benefit cost of $18 an hour, were rapidly becoming vulnerable to severe competitive pressures from lower wage operators," Anderson said in a statement released by the union.

The nation's meatpacking industry was revolutionized in the past decade by the Iowa Beef Processors Inc., a subsidiary of Occidental Petroleum. The non-union firm, which introduced the concept of pre-cut beef, has become a major force in the U.S. meatpacking industry. In the face of the competition from the non-union sector of the industry, UFCWU officials are desperately trying to allow their workers to cling to their lifestyles. For the union meatpacker this probably means no raise for the next four years.

Signs of similar changes already are appearing in the nation's trucking industry where the Teamsters union seems ready to settle on a new three-year contract with little or no guaranteed wage increases. Instead, the union seems willing to settle for the promise of cost-of-living protection in the face of declining inflation. There also are indications the union is willing to give up work rules that have added to employer costs.

Negotiators for the Oil, Chemical and Atomic Workers union, working against a Jan. 7 contract deadline with the nation's oil refinery industry, are seeking an agreement that would give their members a two-year job guarantee.

Perhaps the biggest sign of future change for the American worker this Christmas is in the auto industry, where more than 200,000 workers have been laid off. Bargaining units for the United Auto Workers union will meet in Detroit Jan. 8 to consider reopening contracts with General Motors and Ford. Although the current contracts do not expire until next September, the two auto firms have been demanding the union reopen the contract to grant major wage and benefit concessions. The result of any contract reopener in the auto industry is almost certain to lead to a reduction in the lifestyles, if not the standard of living, of the UAW members involved.

As a prelude to next month's union meetings, General Motors recently announced a sharp cut in benefits for 138,000 salaried employes at the company. For starters, GM ended all paid personal holidays--a concession the company is seeking from the union--reduced vacations by 50 percent and cut some health benefits.

The impact of the new contract cutbacks is not apt to be confined to union workers, however. Any cuts in union contracts next year can be expected to be reflected in the pay and benefits of non-union and salaried workers in companies and industries dealing with the organized industries.