Acherontic vs solemn

Acherontic

adj
  • Lacking joy and comfort; nearing death. 

  • Of, pertaining to or resembling Acheron (one of the rivers located in the underworld according to ancient Greek mythology). 

  • Of or pertaining to hell. 

solemn

adj
  • Deeply serious and sombre; grave. 

  • 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. 

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