Lassitude /(lăs"sĭ*tūd)/

Las·si·tude

Lassitude

n.
  1. A condition of the body, or mind, when its voluntary functions are performed with difficulty, and only by a strong exertion of the will; languor; debility; weariness.
    The corporeal instruments of action being strained to a high pitch . . . will soon feel a lassitude.