refrain vs swear off

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. 

swear off

verb
  • To quit or cease completely, or to promise to quit, as a bad habit. 

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