big hitter
noun [ C ] uk/ˌbɪɡ ˈhɪt.ər/ us/ˌbɪɡ ˈhɪt̬.ɚ/
（尤指某类）要人，重要的事情
an important and influential person or thing (= one with a lot of influence), especially of their particular type
The big hitters in the cast include Michael Caine and Ewan McGregor. 演员阵容中的大牌人物有迈克尔‧凯恩和尤安‧麦格雷戈。