unimportance vs urgency

unimportance

noun
  • Lack of importance. 

urgency

noun
  • The quality or condition of being urgent. 

  • Insistence, pressure, urge. 

  • A sudden and compelling need to urinate that is difficult to defer, associated with conditions such as urinary tract infections and overactive bladder. 

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