1. Excessive or wasteful spending of money: Mark warned his wife that the extravagance of her shopping could result in a shortage of funds for the things that they really needed.
2. Something that is expensive or wasteful: An expensive car can be an extravagance in today's economic conditions.
3. An exaggerated, excessive, or extremely flamboyant nature of something: Mildred's cousin had a wild extravagance and unreasonableness in her speech and behavior.