A Katy is a type of girl who over obsesses with a guy. She does everything EXCEPT talk to him such as: figure out where he hangs out, always walk the way so she'll see him, finds his profile, gets all buggy if he isnt there that day, and constantly talks about him.
She's the type where you can go to her crying saying "OMG MY DOG DIED" and she'll say "HEY! He has a dog!"
Girl: Hey, did you see that one guy? He's so hot. I know so much about him and I've never even talked to him!
Friend: Omg, you're pulling a Katy