The Collaborative International Dictionary of English v.0.48:

Fling \Fling\, n.
   1. A cast from the hand; a throw; also, a flounce; a kick;
      as, the fling of a horse.
      [1913 Webster]

   2. A severe or contemptuous remark; an expression of
      sarcastic scorn; a gibe; a sarcasm.
      [1913 Webster]

            I, who love to have a fling,
            Both at senate house and king.        --Swift.
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   3. A kind of dance; as, the Highland fling.
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   4. A trifing matter; an object of contempt. [Obs.]
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            England were but a fling
            Save for the crooked stick and the gray goose wing.
                                                  --Old Proverb.
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   5. a short period during which one indulges one's wishes,
      whims, or desires in an unrestrained manner.
      [PJC]

   6. a love affair.
      [PJC]

   7. a casual or brief attempt to accomplish something.
      [informal]

   Syn: shot.
        [PJC]

   8. a period during which one tries a new activity; as, he
      took a fling at playing tennis.
      [PJC]

   To have one's fling, to enjoy one's self to the full; to
      have a season of dissipation. --J. H. Newman. "When I was
      as young as you, I had my fling. I led a life of
      pleasure." --D. Jerrold.
      [1913 Webster]