blitzkrieg vs onrush

blitzkrieg and onrush both are nouns.

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

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

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

Other hypernyms of blitzkrieg include attack, onset, onslaught.

blitzkrieg (noun)	onrush (noun)
a swift and violent military offensive with intensive aerial bombardment	(military) an offensive against an enemy (using weapons)
	a forceful forward rush or flow

blitzkrieg (verb)	onrush (verb)
fight a quick and surprising war