PUG stands for Pick-Up Group. A PUG is basically a group of random people who
most likely never met each other before, and they go off to go quest in the
UW, FoW, or even compete in the Tomb of the Primeval Kings, or they can simply
go questing in PvE in the missions or outposts. PUGs are generally not as
good as Guild groups, but often they get the job done if formed right.

EXAMPLE: That PUG has three Monks on their team.