The Collaborative International Dictionary of English v.0.48:

Inextricable \In*ex"tri*ca*ble\, a. [L. inextricabilis: cf. F.
   inextricable. See In- not, and Extricate.]
   [1913 Webster]
   1. Incapable of being extricated, untied, or disentangled;
      hopelessly intricate, confused, or obscure; as, an
      inextricable knot or difficulty; inextricable confusion.
      [1913 Webster]

            Lost in the wild, inextricable maze.  --Blackmore.
      [1913 Webster]

   2. Inevitable. [R.] "Fate inextricable." --Milton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inextricable
    adj 1: not permitting extrication; incapable of being
           disentangled or untied; "an inextricable knot";
           "inextricable unity" [ant: extricable]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "inextricable":
   aground, anchored, caught, chained, enwrapped in mystery, fast,
   fastened, fixed, grounded, held, high and dry, impacted,
   indefinable, inexplicable, insoluble, insolvable, irreducible,
   jammed, moored, mysterious, mystic, packed, stranded, stuck,
   stuck fast, tethered, tied, transfixed, unaccountable, undefinable,
   unexplainable, uninterpretable, unsolvable, wedged