The stock market retreated today, giving up some of last week's gains. The Dow Jones average of 30 industrials, up more than six points at midmorning, was off 14.19 at 2,646.17 by 3 p.m. on Wall Street. The average climbed 96.17 points last week. Losers outnumbered gainers by about 4 to 3 in the overall tally of New York Stock Exchange-listed issues, with 630 up, 845 down and 478 unchanged. Analysts said recent hopes persisted that the economy might avert a recession and start growing at a revived rate as the year passed. But traders also appeared edgy over the interest-rate outlook, especially if business activity should pick up. Rates rose in early trading in the credit markets today. American Express fell 1~ to 27{ in active trading and Shearson Lehman Hutton was down | at 11~. Over the weekend American Express announced plans to reacquire the publicly held shares of Shearson through an exchange of stock. Other losers among the blue chips included American Telephone & Telegraph, down { at 39~; General Motors, down \ at 45}; General Electric, down &rsqb; at 62, and Exxon, down \ at 46{. The NYSE's composite index of all its listed common stocks dropped .93 to 184.04. At the American Stock Exchange, the market value index was up .19 at 356.31. Volume on the Big Board came to 115.97 million shares with an hour to go.