breakthrough vs incursion

breakthrough and incursion both are nouns.

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

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

Other hypernyms of breakthrough include penetration.

breakthrough (noun)	incursion (noun)
a penetration of a barrier such as an enemy's defense	an attack that penetrates into enemy territory
making an important discovery	the act of entering some territory or domain (often in large numbers)
a productive insight	the mistake of incurring liability or blame