What is the meaning of racking?

verb

• Go at a rack.
  • usage: "the horses single-footed"
  • synonyms: single-foot, rack
• Stretch to the limits.
  • usage: "rack one's brains"
  • synonyms: rack
• Put on a rack and pinion.
  • usage: "rack a camera"
  • synonyms: rack
• Obtain by coercion or intimidation.
  • usage: "They extorted money from the executive by threatening to reveal his past to the company boss"; "They squeezed money from the owner of the business by threatening him"
  • synonyms: extort, squeeze, rack, gouge, wring
• Run before a gale.
  • synonyms: scud, rack
• Fly in high wind.
  • synonyms: rack
• Draw off from the lees.
  • usage: "rack wine"
  • synonyms: rack
• Torment emotionally or mentally.
  • synonyms: torment, torture, excruciate, rack
• Work on a rack.
  • usage: "rack leather"
  • synonyms: rack
• Seize together, as of parallel ropes of a tackle in order to prevent running through the block.
  • synonyms: rack
• Torture on the rack.
  • synonyms: rack

adjective

• Causing great physical or mental suffering.
  • usage: "a wrenching pain"
  • synonyms: wrenching