double time vs earnings

double time and earnings both are nouns.

Word	Noun	Adjective	Verb	Adverb
double time	Yes	No	No	Yes
earnings	Yes	No	No	No

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

Other hypernyms of double time include pay, remuneration, salary, wage.

double time (noun)	earnings (noun)
a doubled wage (for working overtime)	something that remunerates
a fast marching pace (180 steps/min) or slow jog	the excess of revenues over outlays in a given period of time (including depreciation and other non-cash expenses)

double time (adverb)	earnings (adverb)
at a faster speed