[Spells help] fatigue

Fatigue is a debilitating weakness that can be brought about by various
effects including the termination of certain spells like haste and giant
strength.  Fatigue is a temporarily loss to an attribute which cannot be
regained by magical means.  This weakness cannot be dispelled - it can 
only be removed through time.  Fatigue can be cumulative if you receive
it more than once, increasing both attributes lost and time fatigued.

See also: attributes haste 'giant strength'