foreshorten vs decrease

foreshorten is not a noun while decrease is a noun.

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

As verbs, decrease is a hypernym of foreshorten; that is, decrease is a word with a broader meaning than foreshorten:

Other hypernyms of foreshorten include lessen, minify.

foreshorten (noun)	decrease (noun)
	the act of decreasing or reducing something
	the amount by which something decreases
	a change downward
	a process of becoming smaller or shorter

foreshorten (verb)	decrease (verb)
reduce in scope while retaining essential elements	decrease in size, extent, or range
shorten lines in a drawing so as to create an illusion of depth	make become smaller