explain vs harass

explain

verb
  • To give a valid excuse for past behavior. 

  • To make plain, manifest, or intelligible; to clear of obscurity; to illustrate the meaning of. 

  • To make something plain or intelligible. 

harass

verb
  • To persistently bother (someone, or a group of people) physically or psychologically when such behaviour is illegal and/or unwanted, especially over an extended period. 

  • To annoy (someone) frequently or systematically; to pester. 

  • To trouble (someone, or a group of people) through repeated military-style attacks. 

  • To put excessive burdens upon (someone); to subject (someone) to anxieties. 

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