#1 extravagance n. [extravagancy] the quality of exceeding the appropriate limits of decorum or probability or truth; "we were surprised by the extravagance of his description". wn #2 extravagance n. [prodigality, profligacy] the trait of spending extravagantly. wn #3 extravagance n. [prodigality, lavishness, highlife, high life] excessive spending. wn