You cannot unequip weapon because its what define your class. Originaly we had the "Adventurer/Squire" class that was for bare-handed purposes, but it was removed during alpha still because makes no sense you having a class unable to change to active mode (because it would have 0 attack, 0 accuracy, etc) and having no actions of its own.

Instead of asking for weapons to become unequipable, lets ask to be able to unequip undies instead! @_@