Collins COBUILD Advanced Learner's English Dictionary - big hitter

also big-hitter 1. A big hitter is a sportsperson such as a golfer or tennis player who hits the ball with a lot of force. The Uruguayan-born big-hitter smashed 28 aces. N-COUNT 2. A big hitter is a powerful or influential person, especially in business or politics. (INFORMAL) ...if Tony Blair fails to persuade a Cabinet big hitter to take on the job. N-COUNT