Intruder /(?)/

In·trud·er

Intruder

n.
  1. One who intrudes; one who thrusts himself in, or enters without right, or without leave or welcome; a trespasser.
    They were all strangers and intruders.
  2. A person who enters a private residence or place of business with the intention to perform a criminal act; as, killed by an intruder.