What is the antonym of parsomonious?

The antonym of parsimonious depends on the specific nuance you want to convey:

For "frugal" or "thrifty":

* Extravagant

* Lavish

* Prodigal

* Indulgent

* Spendthrift

For "stingy" or "cheap":

* Generous

* Open-handed

* Liberal

* Munificent

* Philanthropic

The best antonym for "parsimonious" will depend on the context of the sentence and the specific meaning you want to express.