by herpdyderp December 15, 2010
A verb to describe the action of somebody or something that is acting in a manor that would cause somebody to think that they are mentally handicapped.
When Iryna fell on the floor and started laughing uncontrollably for absolutely no reason, Ryan and Matt mutually agreed that she was derping out.
by NotBigSurprise April 15, 2011
Billy was derping out when he thought his lunchbox was his textbook.
John derped out after getting dizzy.
Matt's derping out!
Bob derped out!
John derped out after getting dizzy.
Matt's derping out!
Bob derped out!
by LAKottke June 10, 2020