internecine vs poisonous

internecine

adj
  • Mutually destructive; most often applied to warfare. 

  • Characterized by struggle within a group, usually applied to an ethnic or familial relationship. 

poisonous

adj
  • Negative, harmful. 

  • Containing sufficient poison to be dangerous to touch or ingest. 

How often have the words internecine and poisonous occurred in a corpus of books? (source: Google Ngram Viewer )