Lassitude
Lassitude (las"si*tūd) , noun
[Latin lassitudo, from lassus faint, weary; akin to English late: compare French lassitude. See Late.]
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.