1. a person who fires a gun or weapon
2. a person who dismisses or terminates an employee from a job
3. a person or device that ignites or sets something on fire

Examples

• The firer aimed carefully before pulling the trigger.
• The company's firer conducted exit interviews with all terminated employees.
• A faulty firer in the engine caused the car to stall repeatedly.
• The firer of the shot was never identified.
• As the firer of the employee, the manager had to document the reasons.
• The firer of the kiln adjusted the temperature to achieve the desired glaze.