Open English Wordnet
Adjectives
(s)grave, sedate, sober, solemndignified and somber in manner or character and committed to keeping promises“a grave God-fearing man”,
“a quiet sedate nature”,
“as sober as a judge”,
“a solemn promise”,
“the judge was solemn as he pronounced sentence” (s)earnest, sincere, solemncharacterized by a firm and humorless belief in the validity of your opinions“both sides were deeply in earnest, even passionate”,
“an entirely sincere and cruel tyrant”,
“a film with a solemn social message”