An example of a closer is the person who shuts down a restaurant at the end of the business day.
An example of a closer is the sales person who goes through the final paperwork to be signed when buying a new car.
In our organization, the VP of Sales usually acts as the closer.
They brought their closer in for the ninth.
The closer of the shop has to lock up.
The DJ chose a fantastic track as his closer at the end of the night.