This is the 17929th most frequent Polish word.
ślepskowi
"Ślepskowi" is the dative form of "Ślepsk," which is a proper noun, often referring to a name, such as a sports team or geographic location. In English, it means "to Ślepsk."
Ślepskowi is the dative form of the proper noun Ślepsk, used here to indicate the indirect object receiving the book.
Oddaję książkę Ślepskowi, bo ją pożyczyłem.
I am returning the book to Ślepsk, because I borrowed it.
Ślepskowi is in the dative case, showing the person being helped or to whom the action is directed.
Pomagam Ślepskowi w przeprowadzce do nowego mieszkania.
I am helping Ślepsk with the move to the new apartment.
The word Ślepskowi again appears in the dative case, designating the recipient of the truth being spoken.