blitz vs onrush

blitz and onrush both are nouns.

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

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

blitz: a swift and violent military offensive with intensive aerial bombardment
onrush: (military) an offensive against an enemy (using weapons)

Other hypernyms of blitz include attack, onset, onslaught.

blitz (noun)	onrush (noun)
a swift and violent military offensive with intensive aerial bombardment	(military) an offensive against an enemy (using weapons)
(American football) defensive players try to break through the offensive line	a forceful forward rush or flow

blitz (verb)	onrush (verb)
attack suddenly and without warning