The Oxford Thesaurus An A-Z Dictionary of Synonyms - extravagancen.

1) wastefulness, waste, lavishness, profligacy, prodigality, squandering, dissipation, improvidence, exorbitance, recklessness, overspending, excess: Our present debts are the result of extravagance. 2) immoderation, immoderateness, excessiveness, outrageousness, unrestraint, superfluity, superfluousness, over-sufficiency, preposterousness, unreasonableness, irrationality, absurdity; capriciousness, whim, fantasy, flightiness: His tawdry life belied the extravagance of his dreams.