depletion vs decrease

depletion and decrease both are nouns.

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

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

Other hypernyms of depletion include diminution, reduction, step-down.

depletion (noun)	decrease (noun)
the act of decreasing something markedly	the act of decreasing or reducing something
the state of being depleted	the amount by which something decreases
	a change downward
	a process of becoming smaller or shorter

depletion (verb)	decrease (verb)
	decrease in size, extent, or range
	make become smaller