Spendthrift

[Sarah]

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.

[Sarah]

–noun

1. a person who spends possessions or money extravagantly or wastefully; prodigal.
   –adjective
2. wastefully extravagant; prodigal.

[Couch Potatoe]

A person who spends money in an extravagant, irresponsible way.

[Lanell]

someone who spends a lot of money in a way that wastes it: