knobhead vs squarehead

knobhead

noun
  • A fool; an idiot; a contemptible person. 

  • The glans penis 

squarehead

noun
  • An honest person; a non-criminal. 

  • A foreigner of Germanic origin, especially a German, Dutch, or Scandinavian person. 

  • A socially conventional or boring person. 

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