behead vs slay

behead

verb
  • To deliberately remove the head of; to cut off (someone's) head. 

slay

verb
  • To eradicate or stamp out. 

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

  • To kill; to murder. 

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

  • To have sex with. 

  • To delight or overwhelm, especially with laughter. 

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