living vs bread and butter

living and bread and butter both are nouns.

Word	Noun	Adjective	Verb	Adverb
living	Yes	Yes	No	No
bread and butter	Yes	No	No	No

As nouns, living and bread and butter are synonyms defined as:

Other synonyms of living include keep, livelihood, support, sustenance.

living (noun)	bread and butter (noun)
the experience of being alive; the course of human events and activities	the financial means whereby one lives
people who are still living
the financial means whereby one lives
the condition of living or the state of being alive

living (adjective)	bread and butter (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