agitator vs overthrower

agitator

noun
  • One who agitates; one who stirs up or excites others, for example political reformers. 

  • An implement for shaking or mixing. 

  • One of a body of men appointed by the army, in Oliver Cromwell's time, to look after their interests. 

overthrower

noun
  • One who overthrows. 

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