He has already achieved his main ambition in life - to become wealthy.

ambition 是名词，意思是"抱负、志向、野心"，指一个人渴望实现的重大目标或成就。这个词来自拉丁语 ambitio，原意是"四处走动争取支持"，后来引申为"追求名誉、权力"的意思。