When a persons expression of his/her face or reaction is considered derping, hence the word "derpface"
Jan: Guess who just got laid?!?
Joe:*makes a derpface, i dont know, you?
Jan: knock off the derpface! your creeping me out!
Joe:*makes a derpface, i dont know, you?
Jan: knock off the derpface! your creeping me out!
by B.H from SPHS October 16, 2011
Get the Derpfacemug. joshua derpface noclipped out of reality and entered your moms basement;
joshua derpface HELP IM IN THE BACKROOMS
joshua derpface HELP IM IN THE BACKROOMS
by spy_who_did_your_mom October 11, 2021
Get the joshua derpfacemug.