Also known as: 異性装, 女装男子, CrossDresser
Wearing clothing traditionally reserved for the opposite sex (e.g. men wearing Dresses, women wearing Tuxedos, etc.)
This is distinct from (but often overlaps with) Trap, which specifically refers to a male convincingly appearing as a female. The crossdressing tag also handles both females in male clothing, and males in female clothing who aren't fooling anyone.
Futanari and Futa Without Pussy are considered to be crossdressing if they are wearing men's clothing.