invisible vs uncognoscible

invisible

adj
  • Unable to be seen; out of sight; not visible. 

  • Not appearing on the surface. 

  • Apparently, but not actually, offline. 

  • That is ignored by a person. 

verb
  • To make invisible, to invisiblize. 

uncognoscible

adj
  • Synonym of incognoscible 

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