The Collaborative International Dictionary of English v.0.48:

Sumptuary \Sump"tu*a*ry\, a. [L. sumptuarius, fr. sumptus
   expense, cost, fr. sumere, sumptum, to take, use, spend; sub
   under + emere to take, buy: cf. F. somptuaire. See Redeem.]
   Relating to expense; regulating expense or expenditure.
   --Bacon.
   [1913 Webster]

   Sumptuary laws or Sumptuary regulations, laws intended to
      restrain or limit the expenditure of citizens in apparel,
      food, furniture, etc.; laws which regulate the prices of
      commodities and the wages of labor; laws which forbid or
      restrict the use of certain articles, as of luxurious
      apparel.
      [1913 Webster]

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

SUMPTUARY LAWS. Those relating to expenses, and made to restrain excess in
apparel.
     2. In the United States the expenses of every man are left to his own
good judgment, and not regulated by Arbitrary laws.