frail vs unsound

frail

adj
  • Weak; infirm. 

  • Mentally fragile. 

  • Liable to fall from virtue or be led into sin; not strong against temptation; weak in resolution; unchaste. 

  • Easily broken physically; not firm or durable; liable to fail and perish. 

noun
  • A basket made of rushes, used chiefly to hold figs and raisins. 

  • A rush for weaving baskets. 

  • The quantity of fruit or other items contained in a frail. 

verb
  • To play a stringed instrument, usually a banjo, by picking with the back of a fingernail. 

unsound

adj
  • Infirm, diseased. 

  • Not whole, not solid, defective. 

  • Not good, unreliable. 

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