windmill

 
Pronunciation: /ˈwɪn(d)mɪl/

noun

  • a building with sails or vanes that turn in the wind and generate power to grind corn into flour.
  • a similar structure used to generate electricity or draw water.
  • British a toy consisting of a stick with curved vanes attached that turn in the wind.

verb

  • (with reference to a person’s arms) move or be moved round in a circle in a manner suggestive of the rotating sails or vanes of a windmill: [with object]: Penny slipped, windmilled her arms, and somehow kept her balance
  • [no object] (of the propeller or rotor of an aircraft, or the aircraft itself) spin unpowered.

Phrases

fling (or throw) one's cap over the windmill (s)

dated act recklessly or unconventionally.