hypostasis vs inwardness

hypostasis and inwardness both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypostasis	Yes	No	No	No
inwardness	Yes	No	No	No

As nouns, inwardness is a hypernym of hypostasis; that is, inwardness is a word with a broader meaning than hypostasis:

hypostasis: (metaphysics) essential nature or underlying reality
inwardness: the choicest or most essential or most vital part of some idea or experience

Other hypernyms of hypostasis include center, centre, core, essence, gist, heart, heart and soul, kernel, marrow, meat, nitty-gritty, nub, pith, substance, sum.

hypostasis (noun)	inwardness (noun)
(metaphysics) essential nature or underlying reality	the quality or state of being inward or internal
any of the three persons of the Godhead constituting the Trinity especially the person of Christ in which divine and human natures are united	preoccupation with what concerns human inner nature (especially ethical or ideological values)
the accumulation of blood in an organ	preoccupation especially with one's attitudes and ethical or ideological values
the suppression of a gene by the effect of an unrelated gene	the choicest or most essential or most vital part of some idea or experience