birdbrained vs hebetate

birdbrained

adj
  • silly and frivolous; empty-headed 

hebetate

adj
  • obtuse; dull 

  • Having a dull or blunt and soft point 

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

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