Noun

1. An employee of a company who creates a large amount of unexpected business, consistently brings in money at critical times, or brings in markedly more money than his or her co-workers, thereby "floating their salaries".
2. An executive or lawyer with exceptional ability to attract clients, use political connections, or increase profits, etc.

   The president has several rainmakers among his advisers.

3. A batted ball that is hit very high to the outfield or beyond the fence.

   The slugger is known for hitting rainmakers.