An experienced salesman who is brought in to "close" the customer by making them agree to a deal. "If I worked with a better closer I'd have more units on the board."

An experienced salesman who is brought in to “close” the sale by making the customer agree to a deal.

a person who takes over for the salesperson to complete the sale

This is the sales manager or an experienced sales person at a dealership who comes in at the end of the negotiation to try and bump the price or "close the deal." The closer has some power but the sales manager has the ultimate power.

The person or persons used to close a deal when the original salesperson is unsuccessful. Often introduced as a manager, another salesperson is often used as a closer.

A salesperson whose job it is to make sure that customers actually buy the car and close the deal.