imperialness vs impressiveness

imperialness and impressiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
imperialness	Yes	No	No	No
impressiveness	Yes	No	No	No

As nouns, impressiveness is a hypernym of imperialness; that is, impressiveness is a word with a broader meaning than imperialness:

imperialness: The quality of being related to an empire, emperor, or empress.
impressiveness: splendid or imposing in size or appearance

Other hypernyms of imperialness include grandness, magnificence, richness.

imperialness (noun)	impressiveness (noun)
The quality of being related to an empire, emperor, or empress.	splendid or imposing in size or appearance
	the quality of making a strong or vivid impression on the mind