silly vs soft-headed

silly

adj
  • Innocent; suffering undeservedly, especially as an epithet of lambs and sheep. 

  • Sickly; feeble; infirm. 

  • Absurdly large. 

  • Laughable or amusing through foolishness or a foolish appearance. 

  • Insignificant, worthless, (chiefly Scotland) especially with regard to land quality. 

  • Stupefied, senseless; stunned or dazed. 

  • Rustic, homely. 

  • Thoughtless, lacking judgment. 

  • Mentally retarded. 

  • Weak, frail; flimsy (use concerning people and animals is now obsolete). 

  • Helpless, defenseless. 

  • Pitiful, inspiring compassion 

  • Very close to the batsman, facing the bowler; closer than short. 

noun
  • A term of address. 

  • A mistake. 

  • A silly person. 

adv
  • Sillily: in a silly manner. 

soft-headed

How often have the words silly and soft-headed occurred in a corpus of books? (source: Google Ngram Viewer )