Derisive term used to describe (usually) avant-garde art that either revels in "shock value" or extreme cleverness. Exactly what constitutes art wank is a point of debate. Some people experience
John Cage's
4'33" as a glorious conceptual piece, others see it a joke, or a purely
academic exercise.
It's a fairly safe bet that any work of art which spends more time explaining itself than simply being a work of art (be it sonic or visual), is probably art wank. If you hear a series of god awful noises followed by a lengthy explanation that these noises were somehow "dedicated to the rainforest", you have been in the middle of art wank.