Multiple Ability Dependency
Multiple Ability Dependency, often shortened to MAD, is a Dungeons & Dragons term that refers to a class or build that requires high scores in many different abilities in order to be effective, as opposed to most classes which are dependent on only one or two. Classes or builds that suffer from MAD are generally underpowered in comparison to more specialised classes, as getting high scores in a large number of attributes is difficult.
The archetypical example is the 3rd Edition Monk, which is dependent on good strength for offensive capability, good dexterity for unarmoured defence, good constitution for hit points, good intelligence to make the best use of his skills list, and good wisdom for both defence and many of his class abiltiies, to say nothing of the charisma needed to roleplay worth a damn.