atrocity vs dreadfulness

atrocity

noun
  • The quality or state of being atrocious; enormous wickedness; extreme criminality or cruelty. 

  • An extremely cruel act; a horrid act of injustice. 

  • An object considered to be extremely unattractive or undesirable. 

dreadfulness

noun
  • The characteristic of being dreadful. 

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