dingleberry vs thickhead

dingleberry

noun
  • A stupid or foolish person. 

  • Vaccinium erythrocarpum, the southern mountain cranberry. 

  • Dried fecal matter adhering to anal hair. 

thickhead

noun
  • Someone stupid. 

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

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