approval vs mistrust

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. 

mistrust

noun
  • Lack of trust or confidence; distrust, untrust. 

verb
  • To be suspicious. 

  • To have no confidence in (something or someone). 

  • To be wary, suspicious or doubtful of (something or someone). 

  • To suspect, to imagine or suppose (something) to be the case. 

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