inexpertness vs knack

inexpertness

noun
  • Lack of expertise or skill. 

knack

noun
  • A petty contrivance; a toy. 

  • A readiness in performance; aptness at doing something. 

  • Something performed, or to be done, requiring aptness and dexterity. 

verb
  • To speak affectedly. 

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