The Collaborative International Dictionary of English v.0.48:

Mottle \Mot"tle\, v. t. [imp. & p. p. Mottled; p. pr. & vb. n.
   Mottling.] [From Mottled.]
   To mark with spots of different color, or shades of color, as
   if stained; to spot; to maculate.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Mottled \Mot"tled\, a. [From Motley.]
   Marked with spots of different colors; variegated; spotted;
   as, mottled wood. "The mottled meadows." --Drayton.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "mottled":
   blotched, blotchy, brindled, calico, clouded, dapple, dappled,
   flecked, freckled, marbled, motley, multicolored, patchy,
   pepper-and-salt, piebald, pied, pinto, skewbald, spattered,
   speckled, splashed, spotted, spotty, sprinkled, stippled, streaked,
   streaky, variegated