I have a nosey neighbor that's always watching me What kind of tree can I plant in front of her window?

She has a one story house. Her side window faces my home. She is so nosey and always watching over here. I hate it. I live in the city. Her window is 4 feet from my property. I don't want anything too big, something that's kinda tall and skinny but will cover her first floor window. Any suggestions?