Top Definition
One who is of little intelligence and/or someone who acts in an unpleasant manner, a derogatory term as to compare someone to a penis inside of a brain.
I was building a giant horse dick in Minecraft and he blew it up with TNT, what a Bonerbrain!
by Duo2Cuo March 15, 2011

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When ones intelligence level decreases as blood flow levels lower in brain to accommodate the needed increased flow to the penis during a erection.
I can't do math right now, I totally have boner-brain.
by JDiddy2Pretty November 11, 2015

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The phenomenon when a males mind becomes filled with extremely sexual thoughts when one has a boner. In other words a person thinks with their boner.
I had a serious case of boner brain in class and almost spunked my pants thinking of fucking Ms. Williams
by TadBitOfThad May 11, 2015

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when one has the inability to speak or function because all of the blood has rushed out of their head to their boner. generally makes the affected person very stupid for the duration of the boner. mainly occurs to men with large schlongs.
"she told me i could touche her boobs and i wigged out, i think i said 'i don't need to.' I NEEDED TO."

"Total boner brain dude, ouch."
by twiceonsundays June 02, 2011

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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).

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