lightness vs sober-mindedness

lightness

noun
  • Levity, frivolity; inconsistency. 

  • The state of having little (or less) weight, or little force. 

  • the relative whiteness or transparency of a colour 

  • Agility of movement. 

  • The product of being illuminated. 

  • Freedom from worry. 

  • the condition of being illuminated 

sober-mindedness

How often have the words lightness and sober-mindedness occurred in a corpus of books? (source: Google Ngram Viewer )