A running into; hence, an entering into a territory with hostile intention; a temporary invasion; a predatory or harassing inroad; a raid.

Attack; occurrence.

the act of entering some territory or domain (often in large numbers); "the incursion of television into the American livingroom"

an attack that penetrates into enemy territory

an invasion, a sudden attack or raid

Attack. "The latest euphemism, 'incursion', is from the vocabulary of lies coined in Vietnam. It means assaulting human beings with tanks and planes." John Pilger, New Statesman, July 1, 02.