Another, lesser known name for a special person. Meant to be as offensive as the word retard. Though it can be used as universally as the word "fuck" such as "Quit being a such herp-a-derp" or "go be a herp-a-derp somewhere else". however the word can be butchered to be simply "herp" or "derp". Although some "herp-a-derps" will reverse the word and say "Derp-a-herp". Saying "Herp-a-derp" as a question changes the meaning to "A retard?" or "That Retard?".
"you herp-a-derp", "Herp-a-derp?", "What the Herp-a-derp?",
Someone who gets around.
A girl with a very slutty background.
Herp-a-derp=girl with herpes or high possibility of having them!
Destiny is a herp-a-derp because she screwed everyone she dates.
Destiny is a herp-a-derp because she flirts with everyone and lets boys get a feel on without giving a crap.
The sound used to describe melee killing somebody in Halo: Reach.
You should have seen me man! I ran up to this bitch and herp-a-derped him good!
GF: Umm... Derp. Let's go to the mall.
L: Kevin your girlfiend is a Herp-a-Derp....
K: No she isn't.