A luxury is a good you consume more of as you get wealthier. For example, environmental regulation is a luxury good, which is why many people don't see the need

A luxury is a good you consume more of as you get wealthier. For example, environmental regulation is a luxury good, which is why many people don't see the need for limiting pollution if it gets in the way of accumulating wealth (and why richer nations tend to have more pollution laws).