liejack
To falsely accuse an opponent or potential critic of the thing that you are saying or doing before they can call you out on the thing that you are saying or doing. Thus, bystanders and third parties become confused and you stand a better chance of getting away with what you are saying or doing.

Also see "liejacking".
The new girl was quietly different, had a lot of piercings and kept to herself. They didn't like the look of her. One girl one day said "she's blatantly secretly a bully and just hasn't found her victim yet". Thus, they began to yell "bullygirl" at her every day at school. Because of this liejack, everyone else just presumed she was a bully that had been found out and some even started to join in. It only stopped when she finally moved schools.