Wearing a cosplay costume, at an inappropriate time/place, to tick off someone you dislike, instead of having a verbal confrontation with them. It works best when used on people who are too stupid to get your reference. Passive aggressive cosplay can be used as an effective form of non-verbal protest.
At the (society for narcissistic mothers) picnic -
Suzy: “Jane, why are you dressed like Joan Crawford?”.
Jane: “Shhhh.... It’s passive-aggressive cosplay”.
At the (society for book-burners) annual brunch -
Rachel: “Jane, why are you dressed like Arya Stark from Game of Thrones?”
Jane: “Shhh.... It’s passive aggressive cosplay”.