This is the 8454th most frequent Polish word.
policyjna
"Policyjna" means "police (adj.)," relating to the police in English.
Here, "policyjna" is used as an adjective describing the van (furgonetka) belonging to or associated with the police.
Na ulicy stoi furgonetka policyjna.
There is a police van parked on the street.
In this sentence, "policyjną" is the feminine instrumental singular form of the adjective, agreeing with the noun "funkcjonariuszka" (female officer), indicating the police-related nature of the profession.
Miałem rozmowę z funkcjonariuszką policyjną.
I had a conversation with a female police officer.
Here, "policyjny" is an adjective modifying "komisariat" (precinct), indicating that it is related to the police.