definition 1: Outside Your Window is a famous song for FNAF made by APAngryPiggy. a youtuber with 123K+ subscribers
definition 2: it might be a threat that someone or your friend might send you to either scare you or they might ACTUALLY BE THERE..
example 1:
person 1: hey! have you heard of "Outside Your Window?"
person 2: yeah! its a great song by APAngryPiggy.
example 2:
friend: hey.. im outside your window
friend 2: are you trying to scare me?! because you surely are!!!