disunite vs mongrelize

disunite

verb
  • To separate, sever, or split. 

  • To cause disagreement or alienation among or within. 

  • To disintegrate; to come apart. 

mongrelize

verb
  • To cross-breed 

  • To breed a mongrel 

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