The Collaborative International Dictionary of English v.0.48:

Snarl \Snarl\, v. t. [imp. & p. p. Snarled; p. pr. & vvb. n.
   Snarling.] [Etymol. uncertain.]
   To form raised work upon the outer surface of (thin metal
   ware) by the repercussion of a snarling iron upon the inner
   surface.
   [1913 Webster]

WordNet (r) 3.0 (2006):

snarled
    adj 1: tangled in knots or snarls; "a mass of knotted string";
           "snarled thread" [syn: knotty, snarled, snarly]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "snarled":
   Byzantine, balled up, complex, complicated, confounded, confused,
   convoluted, crabbed, daedal, devious, disheveled, elaborate,
   embrangled, entangled, fouled up, implicated, intricate, involuted,
   involved, knotted, labyrinthian, labyrinthine, loused up,
   many-faceted, matted, mazy, meandering, messed up, mixed up,
   mucked up, multifarious, mussed up, perplexed, ramified,
   roundabout, ruffled, rumpled, screwed up, shaggy, snaggy, subtle,
   tangled, tangly, tousled, tously, tumbled, twisted, uncombed