A wu jen is a magician in Dungeons & Dragons. The wu jen appeared in the original Oriental Adventures as well as the 3.5 edition update.
A wu jen is much like a wizard, but rather than being focused on academics, wu jen concern themselves with a balance of elements and natural forces. Wu jen were depicted as having to adhere to severe taboos or bans to maintain their powers.
The term wu jen is a neologism with no real world meaning.