thickhead vs wing nut

thickhead

noun
  • Any of several species of Australian songbirds of the genus Pachycephala. 

  • Someone stupid. 

wing nut

noun
  • A nut with wing-like projections to provide leverage in turning with thumb and forefinger. 

  • One who advocates extreme measures or changes, especially if they hold or are perceived to hold far-right viewpoints; a radical or reactionary. 

  • Someone with large, protruding ears. 

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