approval vs conscience

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. 

conscience

noun
  • A personification of the moral sense of right and wrong, usually in the form of a person, a being or merely a voice that gives moral lessons and advices. 

  • The moral sense of right and wrong, chiefly as it affects a person’s own behaviour and forms their attitude to their past actions. 

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