Items (perhaps only heavily randomized object classes, so NOT armor) can be inspected somehow, or else come pre-inspected, and your character is able to conclude that the item is one of a small set of possible things from that object class. The number of these possible things can depend on role, and the “fakes” are randomized every game. This approach is very similar to the one used in the roguelike Golden Krone Hotel.

Example: a character inspects a potion and confirms that it is either healing, acid, or sleeping. All potions with this appearance will provide the same three possibilities. It’s actually acid, but without other identification methods, or ruling out healing and sleeping, it can’t be discerned which of the three it is.

Has some problems with the interface; a character shouldn’t inspect everything and then have to type-name it. Perhaps this could be automated somehow.