The Collaborative International Dictionary of English v.0.48:

Drawback \Draw"back`\, n.
   1. A loss of advantage, or deduction from profit, value,
      success, etc.; a discouragement or hindrance;
      objectionable feature.
      [1913 Webster]

            The avarice of Henry VII . . . . must be deemed a
            drawback from the wisdom ascribed to him. --Hallam.
      [1913 Webster]

   2. (Com.) Money paid back or remitted; especially, a certain
      amount of duties or customs, sometimes the whole, and
      sometimes only a part, remitted or paid back by the
      government, on the exportation of the commodities on which
      they were levied. --M?Culloch.
      [1913 Webster]

WordNet (r) 3.0 (2006):

drawback
    n 1: the quality of being a hindrance; "he pointed out all the
         drawbacks to my plan"

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "drawback":
   abatement, agio, allowance, bank discount, blemish, block,
   blockade, bottleneck, breakage, bug, cash discount, catch,
   chain discount, charge-off, concession, cordon, crack, curtain,
   cut, damage, deduction, defect, defection, deficiency,
   depreciation, determent, deterrent, detriment, difficulty,
   disability, disadvantage, discount, evil, failing, failure, fault,
   faute, flaw, foible, frailty, handicap, hang-up, harm, hazard,
   hindrance, hitch, hole, hurdle, hurt, ill, impairment, impediment,
   imperfection, inadequacy, inconvenience, infirmity, injury, joker,
   kickback, kink, liability, little problem, loss, loss of ground,
   mischief, objection, obstacle, obstruction, obstructive,
   one small difficulty, penalty, penalty clause, percentage,
   prejudice, premium, price reduction, price-cut, problem, rebate,
   rebatement, reduction, refund, rift, rollback, rub, salvage,
   setoff, shortcoming, snag, something missing, step backward,
   stumbling block, stumbling stone, taint, tare, time discount,
   trade discount, tret, trouble, underselling, vulnerable place,
   weak link, weak point, weakness, write-off



Bouvier's Law Dictionary, Revised 6th Ed (1856):

DRAWBACK, com. law. An allowance made by the government to merchants on the
reexportation of certain imported goods liable to duties, which, in some
cases, consists of the whole; in others, of a part of the duties which had
been paid upon the importation. For the various acts of congress which
regulate drawbacks, see Story, L. U. S. Index, h.t.