expenditure vs depletion

expenditure and depletion both are nouns.

Word	Noun	Adjective	Verb	Adverb
expenditure	Yes	No	No	No
depletion	Yes	No	No	No

As nouns, depletion is a hypernym of expenditure; that is, depletion is a word with a broader meaning than expenditure:

expenditure (noun)	depletion (noun)
the act of spending money for goods or services	the act of decreasing something markedly
the act of consuming something	the state of being depleted
money paid out; an amount spent