Queer is an umbrella term for people who are non-heterosexual or non-cisgender. Originally meaning 'strange' or 'peculiar', queer came to be used pejoratively against LGBTQ people in the late 19th century. From Wikipedia
Siwa's candid revelation follows her response to homophobic remarks by Mickey Rourke, who was removed from the show and is now pursuing legal action.
