Top Definition
When someone tries to act all big and cool on the internet by posting offensive and rude posts and comments on forums, youtube, etc. Often done to attempt to feel good about one's sad pathetic lonely life.
Nolifer: "you fucking idiot dont know anything about this go to fucking hell lolol i fuck your mom bitch!!

Human Being: "Stop flexing your internet muscles, everyone knows you aint shit"
by McFondlemeslowly December 18, 2009

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The same as "beer muscles", where when a person is drunk, they do and say things they wouldn't normally have to courage to do, or say. Internet muscles are where a person gets online, reinvents themselves, and says things they can't say in public, like using racial slurs for example.
Khayam can flex his internet muscles and only use the N word, online because he's way too much of a pure coward to ever say it in public to a black person's face.
by ThePac66 September 27, 2011

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Lotsa space for your liquids.

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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.

Buy the t-shirt

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