havering vs impenetrable

havering

adj
  • Hesitant; indecisive. 

  • Long-winded 

noun
  • Indecision, indecisive behaviour. 

impenetrable

adj
  • Incomprehensible; fathomless; inscrutable. 

  • Opaque; obscure; not translucent or transparent. 

  • Not penetrable. 

noun
  • A person not openly given to friendship. 

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