bring down vs decrease

bring down is not a noun while decrease is a noun.

Word	Noun	Adjective	Verb	Adverb
bring down	No	No	Yes	No
decrease	Yes	No	Yes	No

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

Other hypernyms of bring down include lessen, minify.

bring down (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

bring down (verb)	decrease (verb)
cut down on; make a reduction in	decrease in size, extent, or range
impose something unpleasant	make become smaller
cause to be enthusiastic
cause to come to the ground
move something or somebody to a lower position
cause the downfall of; of rulers