poniard vs switchblade

poniard

noun
  • A dagger typically having a slender square or triangular blade. 

verb
  • To stab with a poniard. 

switchblade

noun
  • A folding knife with a blade which opens automatically (under spring pressure) when a button is pressed. 

verb
  • To (cause to) make a sudden move or transition. 

  • To attack or cut with a switchblade. 

  • To spring open or up. 

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