indirectness vs mediacy

indirectness and mediacy both are nouns.

Word	Noun	Adjective	Verb	Adverb
indirectness	Yes	No	No	No
mediacy	Yes	No	No	No

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

indirectness: having the characteristic of lacking a true course toward a goal
mediacy: the quality of being mediate

Other hyponyms of indirectness include allusiveness, mediateness, deviousness, obliqueness, discursiveness, circuitousness.

indirectness (noun)	mediacy (noun)
having the characteristic of lacking a true course toward a goal	the quality of being mediate