fulfill vs refrain

fulfill

verb
  • To obey, follow, comply with (a rule, requirement etc.). 

  • To emotionally or artistically satisfy; to develop one's gifts to the fullest. 

  • To package, distribute, or ship goods. 

  • To satisfy, carry out, bring to completion (an obligation, a requirement, etc.). 

refrain

verb
  • To stop oneself from some action or interference; to abstain. 

  • To abstain from (food or drink). 

noun
  • The chorus or burden of a song repeated at the end of each verse or stanza. 

  • A much repeated comment, complaint, or saying. 

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