extravagance

Buying a diamond-encrusted phone was an unnecessary extravagance that she later regretted.

(Chinese) 买一部镶钻手机是没必要的奢侈，她后来后悔了。

The royal wedding was criticized by some for its extreme extravagance during a recession.

(Chinese) 皇室婚礼因在经济衰退期间极端铺张浪费而遭到一些人的批评。