One who walts it up as a woman. This can take several forms. Some just like to pretend to be women on-line in chat rooms and such like (a 'cyber sex change'). Others actually dress up as women, the most extreme ones having surgery.
Again, similar to above but vice-versa and popular amongst Dieseldykes. For some reason it doesn't cause much public outrage as much as 'Woman Waltism'. Subconsciously, "Man Waltism" is more common as women wear male-based clothes such as jeans, tracksuits etc.