Synonyms for Extravagant (same or very similar meaning)
WordNet sense 1 (recklessly wasteful):
prodigal, profligate, spendthriftWordNet sense 2 (tending to squander and waste):
wastefulWordNet sense 3 (unrestrained, especially with regard to feelings):
excessive, exuberant, overweeningWordNet sense 4 (not subject to restraint):
unrestrainedFrom the ODE community, based on WordNetadd/edit