haecceity vs inwardness

haecceity and inwardness both are nouns.

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

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

haecceity: the essence that makes something the kind of thing it is and makes it different from any other
inwardness: the choicest or most essential or most vital part of some idea or experience

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

haecceity (noun)	inwardness (noun)
the essence that makes something the kind of thing it is and makes it different from any other	the quality or state of being inward or internal
	preoccupation with what concerns human inner nature (especially ethical or ideological values)
	preoccupation especially with one's attitudes and ethical or ideological values
	the choicest or most essential or most vital part of some idea or experience