The female meme version of Derp or Herp. These memes are usually paired up in one set, mostly in the Rage Comics.
Herp: Look at that Derpina right there. God I had a good time with her last night.
Herp da Derp: WTF DERP THAT'S MY MOTHER FUFUFUFUFUFUFUFUFU
feminine version of derp
person 1: i'm so lonely
persona 2: herpderp