1) Debilitating 2) Depleting 3) Exhausting 4) Tiresome 5) Tiring 1) Debilitating 2) Emotionally arduous 3) Exhausting 4) Having a debilitating effect 
• (p. pr. & vb. n.) of Drain • (v. t.) The art of carrying off surplus water, as from land.
Drain'ing verbal noun of Drain , transitive verb (Agriculture) The art of carrying off surplus water, as from land. Draining tile . 
In agriculture, draining is a method of improving the soil by withdrawing the water from it by means of channels that are generally covered over. The successful practice of draining in a great measure depends on a proper knowledge of the superficial strata, of their situation, relative degrees of porosity, etc. Some strata allow water to pass throu...
[adj] - having a debilitating effect
exhausting adjective having a debilitating effect; `an exhausting job in the hot sun`
When curds and whey are separated, and the whey is allowed to drain off.
The process by which whey is drained from the milk solids, just before pressing.