recommendation vs reproof

recommendation

noun
  • An act of recommending. 

  • A suggestion or proposal about the best course of action (with adpositions including "about" for the context and "to" for the course of action) 

  • That which is recommended. 

  • A commendation or endorsement. 

reproof

noun
  • An act or instance of reproving or of reprobating; a rebuke, a reproach, an admonition. 

verb
  • To proof again. 

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