The Collaborative International Dictionary of English v.0.48:

Bespatter \Be*spat"ter\, v. t. [imp. & p. p. Bespattered; p.
   pr. & vb. n. Bespattering.]
   1. To soil by spattering; to sprinkle, esp. with dirty water,
      mud, or anything which will leave foul spots or stains.
      [1913 Webster]

   2. To asperse with calumny or reproach.
      [1913 Webster]

            Whom never faction could bespatter.   --Swift.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bespatter
    v 1: spot, splash, or soil; "The baby spattered the bib with
         food" [syn: spatter, bespatter]

Moby Thesaurus II by Grady Ward, 1.0:

74 Moby Thesaurus words for "bespatter":
   asperge, asperse, attaint, bedabble, bedew, befoul, besmirch,
   bespot, besprinkle, blacken, blot, blow upon, brand, call names,
   censure, dabble, damp, dampen, dash, defame, defile, denigrate,
   dew, disapprove, disparage, douche, engage in personalities,
   expose, expose to infamy, gibbet, hang in effigy, heap dirt upon,
   hose, hose down, humect, humectate, humidify, irrigate, moisten,
   muckrake, paddle, pillory, reprimand, revile, slander, slobber,
   slop, slosh, slur, smear, smirch, soil, sparge, spatter, splash,
   splatter, splotch, sponge, spot, spray, sprinkle, stain,
   stigmatize, sully, swash, syringe, taint, tarnish, throw mud at,
   traduce, vilify, water, wet, wet down