living vs maintenance

living and maintenance both are nouns.

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

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

Other hyponyms of living include amenities, comforts, conveniences, creature comforts, meal ticket, subsistence.

living (noun)	maintenance (noun)
the experience of being alive; the course of human events and activities	activity involved in maintaining something in good working order
people who are still living	the act of sustaining life by food or providing a means of subsistence
the financial means whereby one lives	the unauthorized interference in a legal action by a person having no interest in it (as by helping one party with money or otherwise to continue the action) so as to obstruct justice or promote unnecessary litigation or unsettle the peace of the community
the condition of living or the state of being alive	means of maintenance of a family or group
	court-ordered support paid by one spouse to another after they are separated

living (adjective)	maintenance (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