dissimilarity vs mismatch

dissimilarity

noun
  • Lack of similarity or lack of likeness in appearance to something else. 

mismatch

noun
  • Something that does not match; something dissimilar, inappropriate or unsuitable. 

verb
  • To match unsuitably; to fail to match 

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