Stock prices sagged today in the slowest trading in three weeks, continuing their recent retreat.

The Dow Jones average of 30 industrials, which spent the session hovering just above the 1,200 level, closed at 1,201.41, down 3.54 from Friday's close. Last week, the average dropped 20.98 points.

Volume on the New York Stock Exchange tapered off to 63.20 million shares, down from 83.90 million Friday and the lightest total since 42.11 million changed hands on Oct. 8, when many businesses and investors took a Columbus Day holiday.

Energy stocks were mostly lower in today's trading. Chevron fell 1 1/8 to 32 3/8; Exxon 1/8 to 43 1/8; Mobil 1/8 to 30 5/8; Atlantic Richfield 3/4 to 46 3/4. Texaco rose 1/8 to 34 5/8.

Among airline issues, which have attracted buyers lately amid expectations of lower fuel prices, UAL gained 1/2 to 43; AMR 5/8 to 31 3/8; Delta 5/8 to 36 7/8, and Eastern 1/4 to 5.

Farah Manufacturing tumbled 6 1/2 to 20 3/4, posting the day's largest percentage loss among NYSE issues. The company said Ray Williams, its president and chief executive officer, resigned last week.

Losers outnumbered gainers by more than 3 to 2 in the daily count on the Big Board, and the exchange's composite index lost .28 point to 95.06.