Virulent  (adjective) – actively poisonous; intensely noxious

Sources – http://www.dictionary.com/browse/virulent

Found on page 108, chapter 18. “In her opinion,Helga had lived too long among the enemy, the detestable pale faces. She understood them too well, was too tolerant of their ignorance stupidities. If they had been Latin, Anne might conceivably have forgiven the disloyalty. But Nordics ! Lynchers ! It was too traitorous. Helga smiled a little, understanding Annie’s bitterness and hate, and a little of it cause. It was a piece with that of those she so virulently hated.”

This word was used to describe how Anne was a person and how she affected Helga emotionally. Earlier in the novel, Helga asked Anne why it was bad for a black woman to be with Dr. Anderson. Anne said that the Negro should stick together. Towards the end of the novel, Helga finally sees how toxic her friendship with Anne was. It made it harder for Helga to love herself and accept that she’s biracial and embraces it.