What is the meaning of draining?

verb

• Flow off gradually.
  • usage: "The rain water drains into this big vat"
  • synonyms: drain, run out
• Deplete of resources.
  • usage: "The exercise class drains me of energy"
  • synonyms: drain
• Empty of liquid; drain the liquid from.
  • usage: "We drained the oil tank"
  • synonyms: drain
• Make weak.
  • usage: "Life in the camp drained him"
  • synonyms: enfeeble, debilitate, drain

adjective

• Having a debilitating effect.
  • usage: "an exhausting job in the hot sun"
  • synonyms: exhausting