Recklessly or wastefully extravagant; spendthrift.
Example:
Rodney had been the most prodigal with his expected inheritance and had the most to gain from a redistribution of the estate.
The Latin prodigere means "to squander" -- that is, to "drive away" money and goods. In the biblical story of the prodigal son, the father welcomes home the spendthrift and now-penniless young man, despite his prodigality, just as the Church stands ready to welcome back the repenting sinner. Prodigal can apply to more than money. Farmers may make prodigal use of their soil, or may give their animals prodigal amounts of antibiotics. Rich countries are almost always prodigal with their resources. In a bloody and pointless war, lives are lost on a prodigal scale.