A combination of the words weeaboo (extreme anime fan/Japanophile) and derp (stupid or ignorant person).
Basically...it's used to describe a very stupidanime extremist.
Despite what some people think, there is a bit of a difference between a weeaboo and and a weeaderp.
Normal anime fan: I like Naruto! :)
Weaboo: OMG SQUEE, I LOVE NARUTO!! SO KAWAII! (/^0^)/
Weeaderp: OMG! I luuuuuuuuuuuuuuuuuuuUV animu!!! Especially this one YAOI animu called NArUto! Cuz' every1 nos that Naruto is a yaaaoi! It is KAWAII SUGOI DESUUUU ^///0///^
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).
Precedes or follows either a gratuitously disrespectful or honest remark, originated in New York City. Used in similar fashion to "no offense" or "to be honest," interchangeably.
Ya mans is wild buns, respectfully. Respectfully he's washed.
After school, The Modells on Jamaica Ave was active. Respectfully.