forbidding vs unbefriending

forbidding

adj
  • Appearing to be threatening, unfriendly or potentially unpleasant. 

noun
  • The act by which something is forbidden; a prohibition. 

unbefriending

adj
  • unfriendly; hostile 

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