imperium vs say-so

imperium and say-so both are nouns.

Word	Noun	Adjective	Verb	Adverb
imperium	Yes	No	No	No
say-so	Yes	No	No	No

As nouns, say-so is a hypernym of imperium; that is, say-so is a word with a broader meaning than imperium:

Other hypernyms of imperium include authorisation, authority, authorization, dominance, potency.

imperium (noun)	say-so (noun)
supreme authority; absolute dominion	the power or right to give orders or make decisions
the domain ruled by an emperor or empress; the region over which imperial dominion is exercised	an authoritative declaration
	one chap's arbitrary assertion