This is the 4019th most frequent Polish word.
wojciechem
"Wojciechem" is the instrumental case of the Polish male name "Wojciech," meaning "with Wojciech."
The word 'Wojciechem' is an instrumental case of the name Wojciech, used here to indicate with whom the action of meeting was done.
Spotkałem się z Wojciechem wczoraj.
I met Wojciech yesterday.
Here 'Wojciechem' also appears in instrumental case, used after the preposition 'z' to indicate the person involved in the discussion.
Dyskutowałem z Wojciechem na temat języków obcych.
I discussed with Wojciech about foreign languages.
Again, 'Wojciechem' is in the instrumental case, showing collaboration with the named individual Wojciech in the action of working.