lighthearted vs rocking

lighthearted

adj
  • Joyful, glad, taking pleasure in being alive; not depressed or sad. 

  • Enjoyably lacking of seriousness, not grave. 

rocking

adj
  • Excellent; great. 

  • Shaking, swaying or moving back and forth. 

noun
  • The abrading of a copper plate with a rocker, preparatory to mezzotinting. 

  • The motion by which the design on a steel mill is transferred to a copper cylinder. 

  • The motion of something that rocks. 

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