draw·back /ˈdrɔˌbæk/
  不利點,退稅
  Draw·back n.
  1. A loss of advantage, or deduction from profit, value, success, etc.; a discouragement or hindrance; objectionable feature.
     The avarice of Henry VII . . . . must be deemed a drawback from the wisdom ascribed to him.   --Hallam.
  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.
  ◄ ►
  drawback
       n : the quality of being a hindrance; "he pointed out all the
           drawbacks to my plan"