solemn vs unconcerned

solemn

adj
  • Inspiring serious feelings or thoughts; sombrely impressive. 

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

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

  • Deeply serious and sombre; grave. 

unconcerned

adj
  • Not anxious, apprehensive, or worried. 

  • Having no involvement. 

  • Indifferent and having no interest; aloof. 

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