I read the IllimitableMen's guide to Understanding Narcissism and figured this could have been very effectively applied to particular people in my life. He says the following:

"The best way to deal with a narcopath [...] is to insult and undermine them, amplify their thirst for conflict, question their credibility, mock them and generally degrade their very essence."

Preemptively, however, I realized that this can come off as passive aggressive. Let me give an example:

Her: "You aren't showing me the kind of attention I want!" Me: "Well, I mean, something could be said about someone who's constantly seeking attention and validation... But I won't go there."

^ Is that an example of passive aggression? I worry that it may come off that way. How does one avoid being called passive aggressive, or are there particular situations where passive aggressiveness is simply poorly-framed insulting?