a real Severus Snape
a person who acts like they're the only one who knows what's going on but will make you feel like an idiot if you question them
My science teacher is a real Severus Snape. He said I was stupid for not knowing the answer to the question.
My neighbor is a real Severus Snape. He said he was just helping me with my math homework but I know he's just showing off.
My mom's best friend is a real Severus Snape. She said I was lucky to pass the test but I know she's just waiting for me to fail.