asperse vs backstab

asperse

verb
  • To falsely or maliciously charge another; to slander. 

  • To sprinkle or scatter (liquid or dust). 

backstab

verb
  • to attack someone (especially verbally) unfairly in a deceitful, underhand, or treacherous manner, especially when they're not present in the place or situation that it happens. (as if stabbing them in the back). See backbite. 

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