The Hood was longer, heavier and had the same size guns as the Bismark. Calling it a BC or a BB at that point is a tossup.
The Admiral Class were designed as battlecruisers. After the Battle of Jutland, the deign was changed to allow more armor to deal with plunging fire. With this change, one could call HMS Hood a fast battleship, whereas the Renown and Repulse were obvious battlecruisers. However, Bismark had more armor. More importantly, it didn’t have torpedoes and had more modern range finding equipment. HMS Prince of Wales and Bismark survived hits with relatively little damage. Hood blew up like so many earlier battlecruisers had at Jutland.