Movie stars are often known for their extravagant lifestyles.

extravagant 是形容词，由前缀 extra-（表示"超出"）和词根 vagant（来自拉丁语 vagari，意为"漫游"）组成，字面意思是"超出常规范围的"。引申为"奢侈的、挥霍的"，形容花费或行为超出合理限度。