Solemn

мра́чный

mráčnyj

(cheerless, gloomy, sombre — see also cheerless, gloomy, sombre)

свято́й

svjatój

(religious in nature — see also sacred)

свяще́нный

svjaščénnyj

(religious in nature — see also sacred)

серьёзный

serʹjóznyj

(deeply serious and sombre)

торже́ственный

toržéstvennyj

(characterized by or performed with appropriate or great ceremony or formality)