hebetate vs thick-skulled

hebetate

adj
  • Having a dull or blunt and soft point 

  • obtuse; dull 

verb
  • To render obtuse; to dull; to blunt. 

thick-skulled

adj
  • Dull; heavy; stupid; slow to learn. 

How often have the words hebetate and thick-skulled occurred in a corpus of books? (source: Google Ngram Viewer )