incursion vs onslaught

incursion and onslaught both are nouns.

Word	Noun	Adjective	Verb	Adverb
incursion	Yes	No	No	No
onslaught	Yes	No	No	No

As nouns, onslaught is a hypernym of incursion; that is, onslaught is a word with a broader meaning than incursion:

Other hypernyms of incursion include attack, onrush, onset.

incursion (noun)	onslaught (noun)
an attack that penetrates into enemy territory	(military) an offensive against an enemy (using weapons)
the act of entering some territory or domain (often in large numbers)	the rapid and continuous delivery of linguistic communication (spoken or written)
the mistake of incurring liability or blame	a sudden and severe onset of trouble