1. Derp: Hey man, what were u doing in the market?
Herp: Nothing man. I was just derping around.
2. Mom: Stop derping around on Facebook and study.
Son: Shut up, woman.
Mom: WHAT DID U SAY??? Herp derp.. blah blah.. blah blah.... No XBox for a week.
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.
Verb.
To grin retartedly and/or drool while surrounded by extreme awesomeness because you can not express your joy/excitement/admiration for what ever that is around you with words.
Derived from the words "herp," meaning epic win, and "derp" meaning moment of retardation(according to some definitions).
Commonly occurs when listening to music or watching movies.