bludgeon vs shillelagh

bludgeon

noun
  • A short, heavy club, often of wood, which is thicker or loaded at one end. 

verb
  • To coerce someone, as if with a bludgeon. 

  • To strike or hit with something hard, usually on the head; to club. 

shillelagh

noun
  • A wooden (traditionally blackthorn (sloe) wood) club ending with a large knob. 

  • Any cudgel, whether or not of Irish origin. 

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