knock down vs dump

knock down is not a noun while dump is a noun.

Word	Noun	Adjective	Verb	Adverb
knock down	No	No	Yes	No
dump	Yes	No	Yes	No

As verbs, knock down and dump are synonyms defined as:

Other synonyms of knock down include coldcock, deck, floor.

knock down (noun)	dump (noun)
	a place where supplies can be stored
	(computer science) a copy of the contents of a computer storage device; sometimes used in debugging programs
	a piece of land where waste materials are dumped
	a coarse term for defecation

knock down (verb)	dump (verb)
shatter as if by explosion	knock down with force
knock down with force	drop (stuff) in a heap or mass
cause to come or go down	fall abruptly
	throw away as refuse
	sell at artificially low prices
	sever all ties with, usually unceremoniously or irresponsibly