approval vs qualm

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. 

qualm

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. 

verb
  • To have a sickly feeling. 

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