forbid vs overburden

forbid

verb
  • To disallow; to proscribe. 

  • To oppose, hinder, or prevent, as if by an effectual command. 

  • To deny, exclude from, or warn off, by express command. 

overburden

verb
  • To overload or overtax. 

noun
  • A sterile stratum that lies above the stratum being investigated 

  • The rock and subsoil that lies above a mineral deposit such as a coal seam. 

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