The Collaborative International Dictionary of English v.0.48:

Laugh \Laugh\ (l[aum]f), v. i. [imp. & p. p. Laughed
   (l[aum]ft); p. pr. & vb. n. Laughing.] [OE. laughen,
   laghen, lauhen, AS. hlehhan, hlihhan, hlyhhan, hliehhan; akin
   to OS. hlahan, D. & G. lachen, OHG. hlahhan, lahhan,
   lahh[=e]n, Icel. hl[ae]ja,W Dan. lee, Sw. le, Goth. hlahjan;
   perh. of imitative origin.]
   1. To show mirth, satisfaction, or derision, by peculiar
      movement of the muscles of the face, particularly of the
      mouth, causing a lighting up of the face and eyes, and
      usually accompanied by the emission of explosive or
      chuckling sounds from the chest and throat; to indulge in
      laughter.
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            Queen Hecuba laughed that her eyes ran o'er. --Shak.
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            He laugheth that winneth.             --Heywood's
                                                  Prov.
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   2. Fig.: To be or appear gay, cheerful, pleasant, mirthful,
      lively, or brilliant; to sparkle; to sport.
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            Then laughs the childish year, with flowerets
            crowned.                              --Dryden.
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            In Folly's cup still laughs the bubble Joy. --Pope.
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   To laugh at, to make an object of laughter or ridicule; to
      make fun of; to deride.
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            No wit to flatter left of all his store,
            No fool to laugh at, which he valued more. --Pope.


   To laugh in the sleeve, To laugh up one's sleeve, to
      laugh secretly, or so as not to be observed, especially
      while apparently preserving a grave or serious demeanor
      toward the person or persons laughed at.

   To laugh out, to laugh in spite of some restraining
      influence; to laugh aloud.

   To laugh out of the other corner of the mouth or To laugh
   out of the other side of the mouth, to weep or cry; to feel
      regret, vexation, or disappointment after hilarity or
      exaltation. [Slang]
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