It can be a playful nickname for your rowdy sibling:
Sibling pretends to throw their water bottle at you.
You
flinch and respond with, "Whoa Scary."
-OR-
It can be what you call someone who just... really scares you:
You're standing in line at the grocery store and you catch a hater (or one of your many haters) in the next lane
glaring a hole right through to your soul, making you feel really uncomfortable. "I saw Scary at the store earlier, It was just glaring at me. Just made me feel really uncomfortable, 'bout had to have a
security guard escort me out."
Scary is their name, scary is who they are lol
