To enter a place, especially in large numbers, with the intent of taking control or causing disruption. The army planned to invade the neighboring country at dawn.
To intrude upon or encroach on someone's privacy or personal space. She felt uncomfortable when her colleague tried to invade her personal space during the meeting.
To spread into or over an area in a way that is unwelcome or harmful. The invasive species began to invade the local ecosystem, threatening native plants.