Nah kid
A way to tell someone to take a hike without being a total jerk. It's like you're being nice but still showing them the door.
Nah kid, I'm not joining your TikTok challenge. I don't have time for your nonsense.
Nah kid, I'm not going to the party. I'd rather be alone than be stuck with you.
Nah kid, I'm not helping you with that. You're on your own.