dubious vs ungrounded

dubious

adj
  • Generally considered imprecise or wrong, but not totally unplayable. 

  • Arousing doubt; questionable; open to suspicion. 

  • In disbelief; wavering, uncertain, or hesitating in opinion; inclined to doubt; undecided. 

ungrounded

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

  • Not connected to ground potential 

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