unemotional vs unimpressible

unemotional

adj
  • Showing little or no feeling. 

  • Reasoned and objective, involving reason or intellect rather than feelings. 

unimpressible

adj
  • Not impressible; not sensitive; apathetic. 

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