sedateness vs seriousness

sedateness and seriousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
sedateness	Yes	No	No	No
seriousness	Yes	No	No	No

As nouns, seriousness is a hypernym of sedateness; that is, seriousness is a word with a broader meaning than sedateness:

Other hypernyms of sedateness include earnestness, serious-mindedness, sincerity.

sedateness (noun)	seriousness (noun)
a trait of dignified seriousness	the trait of being serious
	the quality of arousing fear or distress
	an earnest and sincere feeling