Incursion, n.
Etymology: [L. incursio: cf. F. incursion. See Incur.]
1. A running into; hence, an entering into a territory with hostile intention; a temporary invasion; a predatory or harassing inroad; a raid. The Scythian, whose incursions wild Have wasted Sogdiana. Milton. The incursions of the Goths disordered the affairs of the Roman Empire. Arbuthnot.
2. Attack; occurrence. [Obs.] Sins of daily incursion. South.
Syn. -- Invasion; inroad; raid; foray; sally; attack; onset; irruption. See Invasion.
Shades of meaning
Fernald has no entry of its own for incursion; he lists it under attack.
He lists it without comment; the entries above explain its neighbors.