The Collaborative International Dictionary of English v.0.48:

Slouch \Slouch\, v. i. [imp. & p. p. Slouched; p. pr. & vb. n.
   Slouching.]
   1. To droop, as the head.
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   2. To walk in a clumsy, lazy manner. [Colloq.]
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The Collaborative International Dictionary of English v.0.48:

Slouch \Slouch\, v. t.
   To cause to hang down; to depress at the side; as, to slouth
   the hat.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Slouch \Slouch\, n. [Cf. Icel. sl?kra slouching felloew, and E.
   slack, slug, a lazy fellow.]
   1. A hanging down of the head; a drooping attitude; a limp
      appearance; an ungainly, clownish gait; a sidewise
      depression or hanging down, as of a hat brim.
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   2. An awkward, heavy, clownish fellow. [Colloq.]
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   Slouth hat, a soft, limp hat of unstiffened cloth or felt.
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WordNet (r) 3.0 (2006):

slouch
    n 1: an incompetent person; usually used in negative
         constructions; "he's no slouch when it comes to baseball"
    2: a stooping carriage in standing and walking
    v 1: assume a drooping posture or carriage [syn: slump,
         slouch]
    2: walk slovenly