shrinkage vs decrease

shrinkage and decrease both are nouns.

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

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

Other hypernyms of shrinkage include decrement.

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

Other hypernyms of shrinkage include drop-off, lessening.

shrinkage (noun)	decrease (noun)
the act of stealing goods that are on display in a store	the act of decreasing or reducing something
the amount by which something shrinks	the amount by which something decreases
process or result of becoming less or smaller	a change downward
	a process of becoming smaller or shorter

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