The Collaborative International Dictionary of English v.0.48:

Splotch \Splotch\ (spl[o^]ch), n. [Cf. Splash.]
   A spot; a stain; a daub. --R. Browning.
   [1913 Webster]

WordNet (r) 3.0 (2006):

splotch
    n 1: an irregularly shaped spot [syn: blotch, splodge,
         splotch]
    v 1: blotch or spot

Moby Thesaurus II by Grady Ward, 1.0:

147 Moby Thesaurus words for "splotch":
   band, bar, bedabble, bespangle, bespatter, bespeckle, bespot,
   birthmark, blaze, blaze a trail, blemish, bloodstain, blot, blotch,
   blur, brand, caste mark, chalk, chalk up, check, check off,
   checker, checkmark, cicatrix, cicatrize, cut, dab, dabble, dapple,
   dappledness, dappleness, dash, daub, define, delimit, demarcate,
   discolor, discoloration, dot, dottedness, earmark, engrave,
   engraving, eyesore, flake, fleck, flick, flyspeck, freckle,
   freckliness, gash, graving, hack, harlequin, hatch, impress,
   imprint, iris, jot, lentigo, line, macula, maculate, maculation,
   macule, make a mark, marble, marbleize, mark, mark off, mark out,
   marking, mole, motley, mottle, mottledness, nevus, nick, notch,
   patch, pencil, pepper, point, pointillage, pointillism, polka dot,
   polychrome, polychromize, prick, print, punch, punctuate, puncture,
   rainbow, riddle, scar, scarification, scarify, score, scotch,
   scratch, scratching, seal, seam, smear, smirch, smouch, smudge,
   smut, smutch, spangle, spatter, speck, speckle, speckliness,
   splash, splatter, spot, spottedness, spottiness, sprinkle, stain,
   stamp, stigma, stigmatize, stipple, stippledness, stippling,
   strawberry mark, streak, striate, stripe, stud, taint, tarnish,
   tattoo, tattoo mark, tessellate, tick, tick off, tittle, trace,
   underline, underscore, variegate, vein, watermark