existence vs living

existence and living both are nouns.

Word	Noun	Adjective	Verb	Adverb
existence	Yes	No	No	No
living	Yes	Yes	No	No

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

existence (noun)	living (noun)
everything that exists anywhere	the experience of being alive; the course of human events and activities
the state or fact of existing	people who are still living
	the financial means whereby one lives
	the condition of living or the state of being alive

existence (adjective)	living (adjective)
	pertaining to living persons
	(informal) absolute
	still in existence
	(used of minerals or stone) in its natural state and place; not mined or quarried
	true to life; lifelike
	still in active use