assassinate vs slay

assassinate

verb
  • To murder someone, especially an important person, by a sudden or obscure attack, especially for ideological or political reasons. 

  • To harm, ruin, or defame severely or destroy by treachery, slander, libel, or obscure attack. 

slay

verb
  • To kill; to murder. 

  • To defeat; to overcome (in a competition or contest). 

  • To amaze, stun, or otherwise incapacitate by excellence; to excel at something. 

  • To have sex with. 

  • To delight or overwhelm, especially with laughter. 

  • To eradicate or stamp out. 

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