If your friend vacations in lavish hotels, wears thousand-dollar shoes, and refuses to eat cheese that costs less than $20 an ounce, you might say her lifestyle is decadent.
A decadent is a person who has fallen into a state of moral or artistic decay. Typically, though, we use decadent as an adjective to describe wasteful indulgence or extravagance. Celebrities who find themselves unable to manage sudden fame and fortune sometimes go overboard, throwing million-dollar parties, living the fast life, turning to drugs and alcohol. And because they're famous, we read about them and their decadent lifestyles in the tabloid papers.