It's beginning to look a lot like Christmas earlier than ever at area stores.

Seasonal decoration, combined with unusually aggressive sales campaigns, have made the Christmas presence in retail stores visible well before Thanksgiving.

But businessmen and others see these early signs of the holiday as evidence of a bit of fear on the part of retailers about their murkey Christmas season prospects.

Referring to the shopping season, one well-known retailer analyst wondered aloud whether the typical substantial upturn in Christmas business even will materialize.

"If Christmas does come this year, it will be a ho-hum time," he said. "Last Christmas was pretty good, but this year, with retail sales falling out of bed in September and October, well, let's say nobody knows."

In fact, Jeffrey M. Feiner, vice president of Merrill Lynch, Pierce, Fenner & Smith, said in a recent forecasting speech that in light of spiraling consumer debt, continuing high inflation and the limited availability of spendable income, this Christmas will not match the last two.

"The rate of gain in sales is expected to be lower than in the 1977 and 1978 Christmas seasons, partially because of the adverse affects of the sharp increases in Social Security taxes and the expected high bills for gasoline and heating oil," Feiner said.

Furthermore, Feiner predicted that although national consumer merchandise sales rose by about 10.5 percent in the first six months of the year, sales will rise by only about 5 percent during the second half of 1979 despite the holiday season.

Experts say that in particular so-called big-ticket items such as stereo equipment and other large appliances will not sell as well as in previous years, but that items such as do-it-yourself household kits and tools to maintain the home will.

Furthermore some area clothing retailers are continuing to have problems, although those who sell durable work clothes appear to be doing well. In fact, one H Street NE retailer said his sales are up 20 percent over last year as a result of heavy selling of work clothes.

On the other hand, specialists in expensive men's clothing, in particular, have had a hard time because their customers may be shopping for less expensive material or even passing up that new winter suit.

An area wholesale men's wear salesmen said he had no doubt that there would be a "flatness" in the local retail clothing business, noting that inventories are high. "Many of them have enough to sell between now and next Christmas," he said.

The salesman said that the affluent will continue to buy at their favorite stores, but that many consumers are "shopping down" in categories such as young men's suits, buying cheaper clothes at stores without elite reputations. "The clothing business is just plain soft," reported a national stock analyst. "They're damn nervous."

Sidney Lansburgh, president of Raleighs, the area clothing chain with 12 outlets, admits that the men's clothing business has been "sluggish" this fall, although women's apparel has sold well. But he also said that the recent colder weather has been "a shot in the arm" and that business has picked up nicely in the last two weeks.

Noting that he only could speculate on the reasons, Lansburgh said that when "family incomes are pinched," men's clothing suffers "sooner and deeper" than women's or children's wear. "The husband cuts back on himself first," Lansburgh said.

Despite the gloomy predictions, many area merchants say that they expect a successful Christmas season, in part because of the relative economic prosperity of the Washington area and because people here, as elsewhere, consider Christmas spending a personal priority they cannot resist.

William Bederman, the area general manager of Toys-R-Us, which has 11 stores in the Richmond-Baltimore corridor, says his stores will be fully stocked for the Christmas period "despite the purveyors of doom.

"We're in good shape inventory-wise, other than the shortage of chips to manufacture hand-held computer games," Bederman said. "Computer games are particularly good for us because kids are not only customers, but adults are too."

Similarly, Hechinger's, the area's leading home improvement store chain, is experiencing a very successful season. It's success, based on the sales of a variety of tools, housewares and small home appliances under one roof, is a product of a consumer interest in home maintenance and quick, self-service shopping. Notes one analyst: "That's where the action is."

Hechinger's has been a beneficiary of the road-blocks to homebuying as people make the effort to keep their current home in good shape.

And Walter Bell, president of W. Bell & Co. Inc., says there is "no question that we expect a good Christmas season. We have no cause for complaint."

Bell, who runs the catalogue-showroom chain with six stores in the metropolitan area, says jewelry sales in particular are rising this season because "people feel their money is becoming less valuable, so they see something intrinsic and lasting in jewerly as an investment."

Bell said the company's sales of pearls have at least doubled over last year, and sales of good chains, rings and diamonds also have been rising, but at a slower rate.

Further, Bell said he believes that in light of the reluctance to travel far to shop because of high gasoline prices, mail order outfits such as his are destined to thrive.

Like other merchants, Bell indicated that stepped-up advertising is a key to a successful holiday season. Anthony Harriman, vice president and general manager of Neiman Marcus and president the Mazza Gallerie Merchants Association, pointed out that the Friendship Heights shopping center, which features top-line shops and department stores, has engaged in aggressive promotional activities to attract customers.

For example, the association has distributed fliers that promote entertainment within the mall, complimentary drinks and other giveaways at the malls' shops, toy demonstrations and three hours of free parking. That center has expanded from less than 30 stores a year ago to 43.

In additon, the McDonald's fast-food chain will open a Mazza outlet in a couple of weeks. "We're running a lot of ads, but if you look at the other malls, they're doing it, too," Harriman said. "We need traffic just like they do."

Although area merchants say their stocks are high, Merrill Lynch Economics notes in an October report, "Retailing Perspectives," that by cutting their stocks this year, businesses have prepared for any seasonal difficulties.

The analyst said that although they are "forecasting a recessionary environment for the remainder of 1979, we believe that retailers will be prepared for a rather sluggish Christmas selling season because expense and inventory budgets for the fourth quarter of the year appear to be conservative."

Local analysts echo that theme. "Most retailers of general merchandise are playing it close to the vest," said Eliot H. Benson, research director for Ferris & Co. Inc. "They are keeping expectations to a realistic level.

"Businessmen are aware of the talk of recession here or around the corner and have been extremely cautious in what they're buying in anticipation of a relatively flat kind of Christmas season. So they're not going to run into inventory problems."