Which word best describes a person known for wasteful spending?

The term that best describes a person known for wasteful spending is "spendthrift." This word specifically refers to someone who spends money extravagantly and without consideration for saving or budgeting. A spendthrift often indulges in lavish purchases and is characterized by a lack of restraint in financial matters.

In contrast, a saver is someone who is careful with their money and tends to save rather than spend it. An investor is typically someone who spends money with the expectation of generating financial returns, which implies a more strategic approach to spending. A frugal person is known for being economical and avoiding unnecessary expenses. Therefore, "spendthrift" clearly encapsulates the idea of wasteful spending that the question is targeting.