The Collaborative International Dictionary of English v.0.48:

Skulk \Skulk\, n. [Cf. Icel. skollr, skolli, a fox, and E.
   skulk, v.i.]
   A number of foxes together. --Wright.
   [1913 Webster] Skulk

The Collaborative International Dictionary of English v.0.48:

Skulk \Skulk\, Skulker \Skulk"er\, n.
   One who, or that which, skulks.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Skulk \Skulk\, v. i. [imp. & p. p. Skulked; p. pr. & vb. n.
   Skulking.] [Of Scand. origin; cf. Dan. skulke to spare or
   save one's self, to play the truant, Sw. skolka to be at
   leisure, to shirk, Icel. skolla. Cf. Scowl.]
   To hide, or get out of the way, in a sneaking manner; to lie
   close, or to move in a furtive way; to lurk. "Want skulks in
   holes and crevices." --W. C. Bryant.
   [1913 Webster]

         Discovered and defeated of your prey,
         You skulked behind the fence, and sneaked away.
                                                  --Dryden.
   [1913 Webster]

WordNet (r) 3.0 (2006):

skulk
    v 1: lie in wait, lie in ambush, behave in a sneaky and
         secretive manner [syn: lurk, skulk]
    2: avoid responsibilities and duties, e.g., by pretending to be
       ill [syn: malinger, skulk]
    3: move stealthily; "The lonely man skulks down the main street
       all day"