brooding vs frivolous

brooding

adj
  • Broody; incubating eggs by sitting on them. 

  • Deeply or seriously thoughtful. 

noun
  • A spell of brooding; the time when someone broods. 

frivolous

adj
  • Having no reasonable prospect of success because its claim is without merit, lacking a supporting legal or factual basis, while the filing party is, or should be, aware of this. 

  • Of little weight or importance; not worth notice; slight; trivial. 

  • Silly, especially at an inappropriate time or in an inappropriate manner. 

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