powerfulness vs potency

powerfulness and potency both are nouns.

Word	Noun	Adjective	Verb	Adverb
powerfulness	Yes	No	No	No
potency	Yes	No	No	No

As nouns, potency is a hyponym of powerfulness; that is, potency is a word with a more specific, narrower meaning than powerfulness:

powerfulness (noun)	potency (noun)
possession of controlling influence	capacity to produce strong physiological or chemical effects
	the power or right to give orders or make decisions
	the state of being potent; a male's capacity to have sexual intercourse
	the inherent capacity for coming into being