1 definition by Ryan Christopher Cole

noun; derived from the acronym T.B.I. = traumatic brain injury : used to refer to any number of people who happen to be belowe an average level of intelligence, specifically (stupid) girls who love shoes, purses and all things that sparkle and (disgusting) guys whose sole interests include beer, pussy, ignorance and flatulence.
Christopher Reeves was NOT a tibby.
Megan Roome is DEFINITELY a tibby.
by Ryan Christopher Cole December 10, 2006
Get the tibby mug.