birdbrained vs dumb

birdbrained

adj
  • silly and frivolous; empty-headed 

dumb

adj
  • Pointless, foolish, lacking intellectual content or value. 

  • Lacking brightness or clearness, as a colour. 

  • Extremely stupid. 

verb
  • To make stupid. 

  • To represent as stupid. 

  • To reduce the intellectual demands of. 

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