Short for Rat Bastard. Something you would call someone for pulling a shaddy or lame manuever. For example, taking credit for you work at your job.
by sdlakers March 12, 2010
Get the RBmug. by corbet December 28, 2007
Get the RBmug. by swagsarah May 3, 2014
Get the RBSmug. by Llazi-G July 4, 2018
Get the rbmug. 

