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A nerd, to the extreme, putting more emphasis on the person in question's nerdiness.

Put simply, it is the combination of the words "fucking" and "nerd". Fucking nerd = Fnerd.
You know, that guy Jake who works at Kinko's? He would be a lot cooler if he wasn't such a fnerd.
by chaseburgala August 12, 2009
A small piece of fuzz originating from deep inside the pocket of pants, jeans, or trousers.
"Did you want a piece of gum? I have one for you but it's stuck to a piece of fnerd."
by CopyPro July 29, 2009
A New Form Of Nerd, who's X-tremly smart and likes to Fuck alot with other nerds in otherwords he/she gets around alot.
"Dude look at that Fnerd" "Boy Id like to do that Fnerd..she/he'd do me any day.."
by Cat Batz May 21, 2005
A bit of toilet paper caught in the pubic hair, larger than lint, but smaller than a wad.
Cheap toilet paper tends to leave a lot of fnerds. I picked off her fnerds before I kissed her cuchie.
by kejejoro October 12, 2006