flash flood vs deluge

flash flood and deluge both are nouns.

Word	Noun	Adjective	Verb	Adverb
flash flood	Yes	No	No	No
deluge	Yes	No	Yes	No

As nouns, deluge is a hypernym of flash flood; that is, deluge is a word with a broader meaning than flash flood:

flash flood: a sudden local flood of great volume and short duration
deluge: the rising of a body of water and its overflowing onto normally dry land

Other hypernyms of flash flood include alluvion, flood, inundation.

flash flood (noun)	deluge (noun)
a sudden local flood of great volume and short duration	a heavy rain
	the rising of a body of water and its overflowing onto normally dry land
	an overwhelming number or amount

flash flood (verb)	deluge (verb)
	fill or cover completely, usually with water
	charge someone with too many tasks
	fill quickly beyond capacity; as with a liquid