subsist vs subsistence

subsist is not a noun while subsistence is a noun.

Word	Noun	Adjective	Verb	Adverb
subsist	No	No	Yes	No
subsistence	Yes	No	No	No

subsist (noun)	subsistence (noun)
	minimal (or marginal) resources for subsisting
	the state of existing in reality; having substance
	a means of surviving

subsist (verb)	subsistence (verb)
support oneself