Previously, the in-game name of the adamant warhammer was "adamant warhammer" and later as "addy warhammer". This was later changed because of many false bug reports about the misspelling. When the name of the adamant warhammer was changed to "addy warhammer," it was likely due to the fact that the item took up too many characters in the previous game code. Jagex went with "addy" from the nickname players called adamant items.
Like all other adamant weapons, the Adamant warhammer used to require 30 Attack to wield; this was changed to 40 Attack with the Evolution of Combat.