look up any word, like plopping:
A phrase used when someone is being dumb or obviously didn't think out what they were about to say before they said it.
Teacher: "In this story, can anybody tell me what symbolizes death?"
Girl: "Whats death?"
Guy: "Really? You're straight derpin' right now"
by TheHerpaDerp March 22, 2011
The act of doing something in a way that some would say is odd.
Guy1: what is he doing?
Guy2: Derpin'.
by Yoshichu March 15, 2011
To snort a line of crack, or some sort of drug.
Ay man, you're lucky you got crack, I wish I was derpin!
by Hillathug January 22, 2010