invade
This term carries a strong connotation of violation and aggression, regardless of whether the context is military, biological, or social. It suggests a breach of boundaries where the entering force is perceived as hostile, unwanted, or overwhelming, creating a sense of loss of control for the entity being entered.
In non-military usage, the word often describes a sudden, swarm-like influx that disrupts the normal order of a place or a mental state. While "enter" is neutral, "invade" implies an intrusive quality that transforms the space or state of mind into something chaotic or compromised.
Meanings
To enter a country or region by force with an army in order to conquer or occupy it.
To enter a place or a situation in large numbers, often in an unwelcome or intrusive manner.