ungrounded vs unsound

ungrounded

adj
  • Not grounded; without ground or basis, unreal, false. 

  • Not connected to ground potential 

unsound

adj
  • Not whole, not solid, defective. 

  • Infirm, diseased. 

  • Not good, unreliable. 

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