say-so vs potency

say-so and potency both are nouns.

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

As nouns, say-so and potency are synonyms defined as:

Other synonyms of say-so include authorisation, authority, authorization, dominance.

say-so (noun)	potency (noun)
the power or right to give orders or make decisions	capacity to produce strong physiological or chemical effects
an authoritative declaration	the power or right to give orders or make decisions
one chap's arbitrary assertion	the state of being potent; a male's capacity to have sexual intercourse
	the inherent capacity for coming into being