heavy hitter

n.
One that is predominant, as in influence or power: "Especially when a candidate is a challenger, appearances with heavy hitters from the party lend an air of credibility" (Linda Feldmann).

An important or influential individual or organization. For example, This publishing house is one of the heavy hitters in the textbook industry. This expression originated in sports such as boxing, where it literally meant "hitting hard," and was transferred to other enterprises in the mid-1900s.

---

Note: click on a word meaning below to see its connections and related words.

The noun has one meaning:

Meaning #1: an influential person who works hard to promote the causes they are interested in

---