explain vs unhinge

explain

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

  • To give a valid excuse for past behavior. 

  • To make something plain or intelligible. 

unhinge

verb
  • To remove the leaf of a door or a window from its supporting hinges. 

  • To dislocate. 

  • To mentally disturb. 

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