in·vade / inˈvād/ • v. [tr.] (of an armed force or its commander) enter (a country or region) so as to subjugate or occupy it: Iraq's intention to invade Kuwait | [intr.] they would invade at dawn. ∎ enter (a place, situation, or sphere of activity) in large numbers, esp. with intrusive effect: demonstrators invaded the presidential palace. ∎ (of a parasite or disease) spread into (an organism or bodily part). ∎ (of a person or emotion) encroach or intrude on: he felt his privacy was being invaded. DERIVATIVES: in·vad·er n.