closed vs impassable

closed

adj
  • Not operating or conducting trade. 

  • Lacking a free variable. 

  • Formed by closing the mouth and nose passages completely, like the consonants /t/, /d/, and /p/. 

  • Having component words joined together without spaces or hyphens; for example, timeslot as opposed to time slot or time-slot. 

  • Not public. 

  • Sealed, made inaccessible or impassable; not open. 

  • Having an open complement. 

  • To be in a position preventing fluid from flowing. 

  • To be in a position allowing electricity to flow. 

  • Such that its image under the specified operation is contained in it. 

  • Whose first and last vertices are the same, forming a closed loop. 

  • Having the sound cut off sharply by a following consonant, like the /ɪ/ in pin. 

impassable

adj
  • Not usable as legal tender. 

  • Incapable of being overcome or surmounted. 

  • Incapable of being passed over, crossed, or negotiated. 

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