irresolvable vs undefinable

irresolvable

adj

  • Impossible to resolve; insoluble. 

  • Impossible to separate into its component parts. 

undefinable

adj

  • Not definable. 

noun

  • Anything that cannot be defined. 

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