solemnest

Adjective

solemn (comparative solemner or more solemn, superlative solemnest or most solemn)

1. (specifically) Of or pertaining to religious ceremonies and rites; (generally) religious in nature; sacred.
2. (broadly) Characterized by or performed with appropriate or great ceremony or formality.
   • Whereas the accentuated linearism, the angular stylization of the folds, the rhythmical course of the outlining and the solemn frontality conjoined with an air of regality in the pose seem to recall the formal repertory of the Corbolinus Master and his group […]1993, Miklós Boskovits, The Origins of Florentine Painting, 1100-1270, volume 1, page 33
3. (broadly) Deeply serious and sombre; grave.

   Synonyms:

   austere, frightful, demure, serious, grave, earnest, grievous, lack-laughter, thoughtful, sad

   Antonyms:

   lighthearted, unserious

4. (broadly) Inspiring serious feelings or thoughts; sombrely impressive.

   Synonyms:

   awe-inspiring

5. (broadly, obsolete) Cheerless, gloomy, sombre.

   Synonyms:

   cheerless, comfortless, bleak, dark, morose, depressing, desolate, dire, disconsolate, dismal

   Antonyms:

   cheerful, air-headed, blissed out, blissful, enrapt, rapt, cock-a-hoop, delighted, ecstatic, elated