viperish

adj

1. In the manner of a viper.
2. spiteful; treacherous

   “Allwhite is dominated, of course, by its white characters: the high-school mean girls Meagan, Maegan and Megan (abused, bulimic, druggy), their mothers (smothering, manipulative, viperish) and their boyfriends (psychotic, supportive, dissolute).”