dirk vs poniard

dirk

noun
  • A long Scottish dagger with a straight blade. 

verb
  • To stab with a dirk. 

poniard

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

verb
  • To stab with a poniard. 

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