knucklehead vs piff

knucklehead

noun
  • An idiot; a stupid or inept person. 

piff

noun
  • Piffle; nonsense; rubbish. 

verb
  • To throw something vigorously. 

intj
  • An exclamation of annoyance or contempt; pish; pshaw. 

adj
  • good or attractive. 

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