insane vs maniac

insane

adj
  • Used by or relating to insane people. 

  • Causing insanity or madness. 

  • Extremely good; incredibly amazing. 

  • Characterized by insanity or the utmost folly; ridiculous; impractical. 

  • Exhibiting unsoundness or disorder of mind; not sane; utterly mad. 

maniac

noun
  • A fanatic, a person with an obsession. 

  • An insane person, especially one who suffers from a mania. 

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