emptiness vs unimportance

emptiness

noun
  • A nonexistence; a lack of existence. 

  • The state or feeling of being empty. 

  • A void; a nothingness; something lacking existence. 

unimportance

noun
  • Lack of importance. 

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