This is the 324th most frequent Polish word.
kierowca
Driver.
'Kierowca' used here specifies the profession or role of a bus driver.
Rozmawiałem z kierowcą autobusu o jego trasie.
I spoke with the bus driver about his route.
Figurative usage of 'kierowca' representing control or direction in a situation.
Każdy człowiek może być raz w życiu kierowcą własnych decyzji.
Everyone can be the driver of their own decisions at least once in their life.
Here, 'kierowca' is used to denote a person operating a vehicle.