Worse than a brain fart, a brain shart has far worse consequences. A brain shart is doing something completely idiotic but in a key situation, or in a way that brings about serious repercussions.
Who can ever forget Chris Webber's brain shart in the 1993 NCAA championship game in which he called a timeout when his team had none, thereby getting a techinical foul and giving UNC the crown.

Because of a colossal brain shart on air in front of millions, Imus is out of a job and out on his can.
by Mavericklax4 April 27, 2007
Get the Brain Shart mug.
Like a brain fart only worse.
A brain fart is forgetting your wedding anversery when asked.
A brain shart is forgetting you're married.
I had a total brain fart when I thought I forgot where I parked my car. Then I realised it was a brain shart because I don't own a car.
by grogboy April 8, 2016
Get the Brain Shart mug.
When a lack of consideration up front results in a serious mess in the back end.
"We were going to deploy to Production at 4 o'clock, but the developers had a massive Brain Shart and the clean up is going to take hours."
by Rainbow Mamba July 12, 2017
Get the Brain Shart mug.
A brain fart immediately succeeded by verbal diarrhoea.
Becca's brain sharted when she exclaimed "I just had a massive shit in the shower"... she meant toilet.
by rugdealer October 6, 2022
Get the Brain Shart mug.
Similar to a brain fart, only something nonsensical comes out of your mouth during the thought process (aka a brain fart where a little comes out).
Guy 1(in deep thought): Yeep.
Guy 2: What?
Guy 1: Huh? Oh, sorry... I had a brain shart.
by Joshua Sweeney April 24, 2006
Get the Brain shart mug.