frivolous vs weighty

frivolous

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

  • 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. 

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

weighty

adj
  • Important; serious; not trivial or petty. 

  • Rigorous; severe; afflictive. 

  • Heavy (“having a lot of weight”). 

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