it is the common day word for noob or noobie or someone acting like a retard. it derived as someone writing on myspace "wats up baby" but instead was written as "wats u pbaby"
Your friend is playing a video game and loses easily you then call them a "pbaby" or your friend is lacking in common knowledge ur reply is "ur such a pbaby"
by SempaiUchiha May 13, 2007