Source : Webster's Revised Unabridged Dictionary (1913)

Thrifty \Thrift"y\, a. [Compar. {Thriftier}; superl.
   {Thriftiest}.]
   1. Given to, or evincing, thrift; characterized by economy
      and good menegement of property; sparing; frugal.

            Her chaffer was so thrifty and so new. --Chaucer.

            I am glad he hath so much youth and vigor left, of
            which he hath not been thrifty.       --Swift.

   2. Thriving by industry and frugality; prosperous in the
      acquisition of worldly goods; increasing in wealth; as, a
      thrifty farmer or mechanic.

   3. Growing rapidly or vigorously; thriving; as, a thrifty
      plant or colt.

   4. Secured by thrift; well husbanded. [R.]

            I have five hundred crowns, The thrifty hire I saved
            under your father.                    --Shak.

   5. Well appearing; looking or being in good condition;
      becoming. [Obs.]

            I sit at home, I have no thrifty cloth. --Chaucer.

   Syn: Frugal; sparing; economical; saving; careful.

Source : WordNet®

thrifty
     adj 1: careful and diligent in the use of resources [ant: {wasteful}]
     2: mindful of the future in spending money; "careful with
        money" [syn: {careful}]
     [also: {thriftiest}, {thriftier}]

thriftier
     See {thrifty}