This is the 11686th most frequent Polish word.
komentarzem
"Komentarzem" is the instrumental form of "komentarz," meaning "comment" or "remark."
Here, 'komentarzem' is used in the instrumental case to describe the manner in which the additional information was added—in the form of a comment.
Pod tekstem zamieściłem komentarzem kilka dodatkowych informacji.
Under the text, I included some additional information as a comment.
In this sentence, 'komentarzem' in the instrumental case refers to the medium or method used to execute the response—a brief comment.
Autorka odpowiedziała na krytykę krótkim komentarzem.
The author responded to the criticism with a brief comment.
Here, 'komentarzem' is instrumental, describing the nature of the opinion—a characterization of it as a sarcastic comment.