gravity vs levity

gravity

noun
  • The lowness of a note. 

  • The state or condition of being grave; seriousness. 

  • Specific gravity. 

  • The state or condition of having weight; weight; heaviness. 

  • Gravitation, the universal force exercised by two bodies onto each other. 

  • The force at the Earth's surface, of the attraction by the Earth's masses, and the centrifugal pseudo-force caused by the Earth's rotation, resulting from gravitation. 

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. 

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