A fork of Rural Dictionary
Someone who is unable to be changed or adapt, is very annoying, aggressive, belligerent, unreasonable, malicious, a control freak, or rudely intrusive
"She's such a plastic bitch"
Your friend is being honest to you and you were like thinking that she's lying about something, however your thoughts was false.
So you say it that she's not a backstabbing plastic bitch.
Oh she's a good friend, a none backstabbing plastic bitch.