bring down vs lower

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

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

As verbs, bring down and lower are synonyms defined as:

Other synonyms of bring down include get down, let down, take down.

bring down (noun)	lower (noun)
	the lower of two berths

bring down (adjective)	lower (adjective)
	the bottom one of two

bring down (verb)	lower (verb)
cut down on; make a reduction in	make lower or quieter
impose something unpleasant	set lower
cause to be enthusiastic	cause to drop or sink
cause to come to the ground	move something or somebody to a lower position
move something or somebody to a lower position	look angry or sullen, wrinkle one's forehead, as if to signal disapproval
cause the downfall of; of rulers