living wage vs earnings

living wage and earnings both are nouns.

Word	Noun	Adjective	Verb	Adverb
living wage	Yes	No	No	No
earnings	Yes	No	No	No

As nouns, earnings is a hypernym of living wage; that is, earnings is a word with a broader meaning than living wage:

living wage: a wage sufficient for a worker and family to subsist comfortably
earnings: something that remunerates

Other hypernyms of living wage include pay, remuneration, salary, wage.

living wage (noun)	earnings (noun)
a wage sufficient for a worker and family to subsist comfortably	something that remunerates
	the excess of revenues over outlays in a given period of time (including depreciation and other non-cash expenses)