airhead vs sadcase

airhead

noun
  • A foolish, silly, or unintelligent person. 

  • A (usually temporary) landing area for aircraft for supplying a non-military operation. 

  • An area of hostile territory that has been seized for use as an airbase to ensure the further safe landing of troops and materiel. 

sadcase

noun
  • A pathetic, unfashionable or socially inept person. 

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