wastage vs decrease

wastage and decrease both are nouns.

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

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

Other hypernyms of wastage include decrement.

wastage (noun)	decrease (noun)
anything lost by wear or waste	the act of decreasing or reducing something
the process of wasting	the amount by which something decreases
	a change downward
	a process of becoming smaller or shorter

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