Definition of "derpy"

I bet that derpy editor had tons of free time and didn’t even try to run (the place).

2011 October 12, Nina Feng, “This One is for You, Fartface”, in Daily Bull (Michigan Technological University)‎, retrieved 2013-05-30

He's drawn Dwayne as a cave-man. A really derpy, mugly caveman, with a sloping forehead, a drooling mouth and Dwayne's buzz cut.

2013 April 25, Katie Hayoz, Untethered, Dystel & Goderich Literary Management, page 107

The other one is a video titled ”I’m Sucking On A Sour Patch Kid Listening To Music Getting Ready For Tonight” featuring DJ Encore’s “I See Right Through You” and the incredibly derpy faces of Bynes. Like most wrecks, it’s hard to look away.

2013 May 3, “6 degrees (no Bacon): Jewish celebrity roundup”, in Heritage Florida Jewish News‎, retrieved 2013-05-30