This is the 7308th most frequent Polish word.
kamińskim
"Kamińskim" is the instrumental or locative case form of the Polish surname "Kamiński," meaning "with Kamiński" or "about Kamiński."
In this sentence, 'Kamińskim' is the instrumental form, used after the preposition 'z' when referring to interacting with someone.
Wczoraj rozmawiałem z panem Kamińskim.
Yesterday, I spoke with Mr. Kamiński.
Here, 'Kamińskim' is the locative form, indicating a location, derived from the name of the street.
Jego dom znajduje się przy ul. Kamińskim.
His house is located on Kamiński Street.
In this case, 'Kamińskim' is a form used to refer to a family name in relation with the preposition 'z' for specifying companionship or association.