efficacy vs effectualness

efficacy and effectualness both are nouns.

Word	Noun	Adjective	Verb	Adverb
efficacy	Yes	No	No	No
effectualness	Yes	No	No	No

As nouns, effectualness is a hypernym of efficacy; that is, effectualness is a word with a broader meaning than efficacy:

efficacy: capacity or power to produce a desired effect
effectualness: power to be effective; the quality of being able to bring about an effect

Other hypernyms of efficacy include effectiveness, effectivity, effectuality.

efficacy (noun)	effectualness (noun)
capacity or power to produce a desired effect	power to be effective; the quality of being able to bring about an effect