flood in vs flood

flood in is not a noun while flood is a noun.

Word	Noun	Adjective	Verb	Adverb
flood in	No	No	Yes	No
flood	Yes	No	Yes	No

flood in (noun)	flood (noun)
	the act of flooding; filling to overflowing
	a large flow
	light that is a source of artificial illumination having a broad beam; used in photography
	the occurrence of incoming water (between a low tide and the following high tide)
	the rising of a body of water and its overflowing onto normally dry land
	an overwhelming number or amount

flood in (verb)	flood (verb)
arrive in great numbers	cover with liquid, usually water
	become filled to overflowing
	fill quickly beyond capacity; as with a liquid
	supply with an excess of