gist vs quiddity

gist and quiddity both are nouns.

Word	Noun	Adjective	Verb	Adverb
gist	Yes	No	No	No
quiddity	Yes	No	No	No

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

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

Other hyponyms of gist include bare bones, hypostasis, haecceity, quintessence, stuff.

gist (noun)	quiddity (noun)
the choicest or most essential or most vital part of some idea or experience	the essence that makes something the kind of thing it is and makes it different from any other
the central meaning or theme of a speech or literary work	an evasion of the point of an argument by raising irrelevant distinctions or objections