This is the 4637th most frequent Polish word.
mną
"Mną" means "me" or "with me" (instrumental case of "ja").
In this sentence, 'mną' is the instrumental case of 'ja', used after the preposition 'ze' to mean 'with me'.
Chodź na spacer ze mną.
Come for a walk with me.
Here, 'mną' is used to indicate the object 'me' in instrumental case regarding an action involving myself, emphasizing introspection.
Jestem zachwycony rozmową z mną samym.
I am delighted with the conversation with myself.
In this example, 'mną' refers to the speaker as the recipient in an interaction where 'with' is the connecting relation.