Popularized by internet personality Hannah Montoya, the "Toxic Chill Girl" tries to act cool, calm and collected, with the aim of trying to present herself as superior to others. She simultaneously insults and degrades others in indirect ways, often times by belittling things they find interesting or exciting.
You: "Did you see that new movie it was so cool!"
Toxic Chill Girl: "That movie was so bad, actually. And can you, like, calm down? You're like, literally yelling."
A girlfriend who constantly starts an argument with her boyfriend, gets jealous quickly, tries to make you mad, etc. She tells you not to do something but she does it, She makes jokes that make you mad, She talks to other guys, She is very jealous.
Gf: Who was that girl you were talking to earlier?
Bf: My friend
Gf: Who?
Bf: (her name)
Gf: (gets mad, catches an attitude)
Bf: But don’t you have a boy best friend? Why are you mad? Your a toxic girlfriend.