incompetent vs nobody’s fool

incompetent

adj
  • Not resistant to deformation or flow. 

  • Unable to make rational decisions; insane or otherwise cognitively impaired. 

  • Opening too early during pregnancy, resulting in miscarriage or premature birth. 

  • Unskilled; lacking the degree of ability that would normally be expected. 

noun
  • A person who is incompetent. 

nobody’s fool

How often have the words incompetent and nobody’s fool occurred in a corpus of books? (source: Google Ngram Viewer )