Top Definition
An acronym which means Full Of Shit Kid.
A FOSK is someone who constantly tells stories about their life to strangers, even though the stories are false. The stories can range from hooking up with a mass number of girls to knowing the name of every star in the sky.
This word is usually used to talk about the said person in thier presence.
Everyone knows FOSK is lying when he says he's not a virgin.
by P. K. Moore July 15, 2008

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Any mannerism made by Ryan Heite.
Ryan (FOSK): I totally got to third base with her when this big bull cam up and rammed me. It's ok, I killed it and fed it to my tame lioness, Shiba.
by D. H. J. H. Johnson August 29, 2008

The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Lotsa space for your liquids.

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The Urban Dictionary Mug

Your favorite word on a white mug.

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The Urban Dictionary Mug

One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.

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The Urban Dictionary T-Shirt

Soft and offensive. Just like you.

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The Urban Dictionary T-Shirt

Smooth, soft, slim fit American Apparel shirt. Custom printed. 100% fine jersey cotton, except for heather grey (90% cotton).

Buy the t-shirt