overturn vs unhorse

overturn

verb
  • To reverse (a decision); to overrule or rescind. 

  • To turn over, capsize or upset. 

  • To diminish the significance of a previous defeat by winning; to make a comeback from. 

  • To overthrow or destroy. 

  • Of a body of water: to undergo a limnic eruption, where dissolved gas suddenly erupts from the depths. 

noun
  • The overturning or overthrow of some institution or state of affairs; ruin. 

  • A turning over or upside-down; inversion. 

unhorse

verb
  • To disrupt or unseat; to remove from a position. 

  • To forcibly remove from a horse. 

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