alter vs supersede

alter

verb
  • To become different. 

  • To castrate, neuter or spay (a dog or other animal). 

  • To change the form or structure of. 

  • To tailor clothes to make them fit. 

  • To affect mentally, as by psychotropic drugs or illness. 

noun
  • An identity or headmate of a person with dissociative identity disorder (previously known as multiple personality disorder). A member of a system. 

supersede

verb
  • To displace in favour of itself. 

  • To take the place of. 

noun
  • An updated newsgroup post that supersedes an earlier version. 

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