onrush vs spate

onrush and spate both are nouns.

Word	Noun	Adjective	Verb	Adverb
onrush	Yes	No	No	No
spate	Yes	No	No	No

As nouns, spate is a hypernym of onrush; that is, spate is a word with a broader meaning than onrush:

Other hypernyms of onrush include rush, surge, upsurge.

onrush (noun)	spate (noun)
(military) an offensive against an enemy (using weapons)	the occurrence of a water flow resulting from sudden rain or melting snow
a forceful forward rush or flow	a sudden forceful flow
	(often followed by `of') a large number or amount or extent