solemn vs unofficial

solemn

adj
  • Characterized by or performed with appropriate or great ceremony or formality. 

  • Of or pertaining to religious ceremonies and rites; (generally) religious in nature; sacred. 

  • Inspiring serious feelings or thoughts; sombrely impressive. 

  • Deeply serious and sombre; grave. 

unofficial

adj
  • Not officially established. 

  • Not acting with official authority. 

  • Implicitly true but withheld and/or contradicted by authority. 

  • Not listed in a national pharmacopeia etc. 

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