Source : Webster's Revised Unabridged Dictionary (1913)

Spendthrift \Spend"thrift`\, n.
   One who spends money profusely or improvidently; a prodigal;
   one who lavishes or wastes his estate. Also used
   figuratively.

         A woman who was a generous spendthrift of life. --Mrs.
                                                  R. H. Davis.

Spendthrift \Spend"thrift\, a.
   Prodigal; extravagant; wasteful.

Source : WordNet®

spendthrift
     adj : recklessly wasteful; "prodigal in their expenditures" [syn:
           {extravagant}, {prodigal}, {profligate}]
     n : someone who spends money prodigally [syn: {spend-all}, {spender},
          {scattergood}]