The Collaborative International Dictionary of English v.0.48:

Droop \Droop\ (dr[=oo]p), v. i. [imp. & p. p. Drooped; p. pr.
   & vb. n. Drooping.] [Icel. dr[=u]pa; akin to E. drop. See
   Drop.]
   1. To hang bending downward; to sink or hang down, as an
      animal, plant, etc., from physical inability or
      exhaustion, want of nourishment, or the like. "The purple
      flowers droop." "Above her drooped a lamp." --Tennyson.
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            I saw him ten days before he died, and observed he
            began very much to droop and languish. --Swift.
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   2. To grow weak or faint with disappointment, grief, or like
      causes; to be dispirited or depressed; to languish; as,
      her spirits drooped.
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            I'll animate the soldier's drooping courage.
                                                  --Addison.
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   3. To proceed downward, or toward a close; to decline. "Then
      day drooped." --Tennyson.
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The Collaborative International Dictionary of English v.0.48:

Droop \Droop\, v. t.
   To let droop or sink. [R.] --M. Arnold.
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         Like to a withered vine
         That droops his sapless branches to the ground. --Shak.
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The Collaborative International Dictionary of English v.0.48:

Droop \Droop\, n.
   A drooping; as, a droop of the eye.
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WordNet (r) 3.0 (2006):

droop
    n 1: a shape that sags; "there was a sag in the chair seat"
         [syn: sag, droop]
    v 1: droop, sink, or settle from or as if from pressure or loss
         of tautness [syn: sag, droop, swag, flag]
    2: hang loosely or laxly; "His tongue lolled" [syn: droop,
       loll]
    3: become limp; "The flowers wilted" [syn: wilt, droop]