levity vs urgency

levity

noun
  • A lighthearted or frivolous act. 

  • The state or quality of being light, buoyancy. 

  • Lightness of manner or speech, frivolity; lack of appropriate seriousness; inclination to make a joke of serious matters. 

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 levity and urgency occurred in a corpus of books? (source: Google Ngram Viewer )