approve vs cavil

approve

verb
  • To consider worthy (to); to be pleased (with); to accept. 

  • To officially sanction; to ratify; to confirm; to set as satisfactory. 

  • To make profit of; to convert to one's own profit — said especially of waste or common land appropriated by the lord of the manor. 

  • To regard as good; to commend; to be pleased with; to think well of. 

cavil

verb
  • To criticise for petty or frivolous reasons. 

noun
  • A petty or trivial objection or criticism. 

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