pug is an acronym for pick up group, not public group. same meaning, i guess, but you seemed to not know.
while were on the topic, i hate the term noob. I AM old school... as i still like the term Rookie.
I used to like "scrub" as a term, long berfore internet times, but its gotten played-out (theres a term that should date me)
Pub is an in-game terms used by NPCs to refer to Rebublic. just as Imp is used in-game for Imperials. hard to change terms creaed BY the game.