drone vs sermonize

drone

verb
  • To speak in a monotone way. 

  • To produce a low-pitched hum or buzz. 

  • To kill with a missile fired by unmanned aircraft. 

noun
  • One of the fixed-pitch pipes on a bagpipe. 

  • One who performs menial or tedious work. 

  • A person without the ability to think critically and independently, especially one who follows a group blindly; a non-player character. 

  • A remotely controlled aircraft, an unmanned aerial vehicle (UAV). 

  • A Toyota HiAce or a similar van, especially one used by Ugandan state agents to kidnap opposition members. 

  • A male ant, bee or wasp, which does not work but can fertilize the queen. 

  • A genre of music that uses repeated lengthy droning sounds. 

  • A humming or deep murmuring sound. 

  • A low-pitched hum or buzz. 

sermonize

verb
  • To say in the manner of a sermon or lecture. 

  • To preach a sermon to (somebody); to give (somebody) instruction or admonishment on the basis of one's morality or opinions. 

  • To speak in the manner of a sermon; to preach; to propagate one's morality or opinions with speech. 

  • To inculcate rigid rules. 

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