abstain vs swear off

abstain

verb
  • Refrain from (something or doing something); keep from doing, especially an indulgence. 

  • Deliberately refrain from casting one's vote at a meeting where one is present. 

swear off

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

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