Peter did not know the man's name. He was not insulting him by calling him "Man." If people would think he was insulting him, you could use a culturally acceptable way for a man to address a man he does not know, or you could leave out the word. See how you translated this in [Luke 22:58](../22/58.md).
"I do not know what you are talking about." This expression means that Peter completely disagrees with the man. Alternate translation: "what you said is not true at all" or "what you said is completely false" (See: [[rc://en/ta/man/jit/figs-idiom]])