The Collaborative International Dictionary of English v.0.48:

Stark \Stark\ (st[aum]rk), adv.
   Wholly; entirely; absolutely; quite; as, stark mad. --Shak.
   [1913 Webster]

         Held him strangled in his arms till he was stark dead.
                                                  --Fuller.
   [1913 Webster]

   Stark naked, wholly naked; quite bare.
      [1913 Webster]

            Strip your sword stark naked.         --Shak.
      [1913 Webster]

   Note: According to Professor Skeat, "stark-naked" is derived
         from steort-naked, or start-naked, literally
         tail-naked, and hence wholly naked. If this etymology
         be true the preferable form is stark-naked.
         [1913 Webster]

WordNet (r) 3.0 (2006):

stark naked
    adj 1: (used informally) completely unclothed [syn: bare-
           assed, bare-ass, in the altogether, in the buff,
           in the raw, raw, peeled, naked as a jaybird,
           stark naked]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "stark naked":
   bald, bare, bare-ass, gymnosophical, in native buff,
   in puris naturalibus, in the altogether, in the buff, in the raw,
   naked, naturistic, nude, nudist, peeled, raw, stripped, unclad,
   unclothed, undressed, with nothing on, without a stitch