abstain vs leave 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. 

leave off

verb
  • To desist; to cease. 

  • To omit. 

  • To stop with a view to resuming at a later point. 

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