penetrate or assault, in a harmful or injurious way; "The cancer had invaded her lungs"
To attack; to infringe; to encroach on; to violate; as, the king invaded the rights of the people
To enter with hostile intentions; to enter with a view to conquest or plunder; to make an irruption into; to attack; as, the Romans invaded Great Britain
If you say that people or animals invade a place, you mean that they enter it in large numbers, often in a way that is unpleasant or difficult to deal with. People invaded the streets in victory processions almost throughout the day
occupy in large numbers or live on a host; "the Kudzu plant infests much of the South and is spreading to the North"
To invade a country means to enter it by force with an army. In autumn 1944 the allies invaded the Italian mainland at Anzio and Salerno The Romans and the Normans came to Britain as invading armies
march aggressively into another's territory by military force for the purposes of conquest and occupation; "Hitler invaded Poland on September 1, 1939"
to intrude upon, infringe, encroach on, violate; "This new colleague invades my territory"; "The neighbors intrude on your privacy"