Intrusion (noun)

1. An instance of entering someone's property or territory without right or permission.
2. The act of disrupting a system or situation with an unwelcome or unnecessary element.
3. The act of breaking into a computer system.
4. An unwelcome or inappropriate insertion or occurrence.

Origin:

Late 16th century (in the sense "an incursion"): from latin intrusio(n-), from intrudere "to thrust in".

Examples:

1. The intruder's intrusion into the private property resulted in the homeowner calling the police.
2. The sudden intrusion of reality into their fantasy world was a harsh reminder of the world they actually lived in.
3. A successful intrusion into the computer system can result in sensitive information being stolen.
4. His constant interruptions during the meeting were seen as an intrusion into the business proceedings.
5. Her sudden intrusion into the conversation was seen as rude and unwanted.