look up any word, like the eiffel tower:
1. A brain which is actually filled with nothing but piss.
2. Some idiot who has pissed on his brains.
3. A good name to call a dunce.
4. Useless fool.
A dumbass who has verbal diarrhoea. (good name to call someone, i.e. your best pal)
by Mr Piss-Brains January 29, 2004
Similar to a peabrain but with a much greater measure of stupidity; only a true retard could be a pissbrain.

May also be used to describe some asshaberdasher who actually urinates into his brain by connecting a small-diameter hose from their ding-a-ling (or peehole) to one of their ears (probably one with a busted tympanic membrane {eardrum}) and then passing micturition through rhe tube; thus filling their cranium with piss..
Geez, look at Horhay over there attempting to force a triangular peg through a circular opening! What a fucking pissbrain!
by Telephony March 08, 2014
(n) The distracted mental state resulting from a serious need to urinate. Usually resulting in a delay to relieving said need.
I totally screwed up the last 3 answers on the exam because I had Piss Brain.

My Piss Brain was so acute I had a hard time unzipping my pants.
by barfeedbob October 06, 2011