approval vs strife

approval

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

  • 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. 

strife

noun
  • Exertion or contention for superiority, either by physical or intellectual means. 

  • A trouble of any kind. 

  • Striving; earnest endeavor; hard work. 

  • Bitter conflict, sometimes violent. 

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