This is the 10280th most frequent Polish word.
cesarzem
"Emperor."
The word 'cesarzem' here is used as the instrumental case of 'cesarz' indicating the role or title of someone as an emperor.
On był ostatnim cesarzem rzymskim przed upadkiem cesarstwa.
He was the last Roman emperor before the empire's fall.
Here, 'cesarzem' is employed in the instrumental case, specifying the aspirational state or designation someone dreams of.
Marzę o tym, żeby być cesarzem wielkiego kraju.
I dream of being the emperor of a great country.
In this sentence, 'cesarzem' is used in the instrumental case, describing the person one had an encounter with.