alter vs refine

alter

verb
  • To tailor clothes to make them fit. 

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

  • To change the form or structure of. 

  • To become different. 

  • 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. 

refine

verb
  • To make nice or subtle. 

  • To improve in accuracy, delicacy, or excellence. 

  • To become pure; to be cleared of impure matter. 

  • To purify of coarseness, vulgarity, inelegance, etc.; to polish. 

  • To purify; reduce to a fine, unmixed, or pure state; to free from impurities. 

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