mistrust vs qualm

mistrust

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

  • To be suspicious. 

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

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

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

qualm

verb
  • To have a sickly feeling. 

noun
  • A prick of the conscience; a moral scruple, a pang of guilt. 

  • A feeling of apprehension, doubt, fear etc. 

  • A sudden sickly feeling; queasiness. 

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