approval vs reversal

approval

noun
  • Something mailed by a seller to a collector to match their stated interests; the collector can approve of or return the item. 

  • An expression granting permission; an indication of agreement with a proposal; an acknowledgement that a person, thing, or event meets requirements. 

  • An expression of favorable acceptance and encouragement; a compliment that also condones. 

reversal

noun
  • A change in fortune; a change from being successful to having problems. 

  • An instance of reversing. 

  • The state of being reversed. 

adj
  • Intended to reverse; implying reversal. 

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