by Phuqit November 12, 2006
One of three categorizations of an answer (other two: anus and brain--see definition); meaning you are not 100% certain that your answer is 100% true
by spintas March 12, 2012
Tom's decision to wear a leisure suit to his father-in-law's funeral clearly came out of his brainus.
by Antonym Antony January 31, 2011
noun - the pseudo-brain you have in your anus, that you inadvertently use to make stupid decisions or make you say stupid things, as opposed to using your actual brain. (2)Name used to describe someone who used his/ass and therefore "brainus" to make a decision that was stupid.
by Jonathan Ainslie August 13, 2006
by Roddy von Seldeneck May 5, 2007
by Tiahlm September 10, 2007
Honestly, I really do not know how I came up with that figure, must have been using my brainus that day.
by Motosaki410 June 5, 2019