flawless vs unsound

flawless

adj
  • Without flaws, defects, or shortcomings; perfect. 

unsound

adj
  • Not whole, not solid, defective. 

  • Infirm, diseased. 

  • Not good, unreliable. 

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