flood vs flood in

flood is a noun but flood in is not a noun.

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

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