The Collaborative International Dictionary of English v.0.48:

Smirch \Smirch\, v. t. [From the root of smear.]
   To smear with something which stains, or makes dirty; to
   smutch; to begrime; to soil; to sully.
   [1913 Webster]

         I'll . . . with a kind of umber smirch my face. --Shak.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Smirch \Smirch\, n.
   A smutch; a dirty stain.
   [1913 Webster]

WordNet (r) 3.0 (2006):

smirch
    n 1: a blemish made by dirt; "he had a smudge on his cheek"
         [syn: smudge, spot, blot, daub, smear, smirch,
         slur]
    2: an act that brings discredit to the person who does it; "he
       made a huge blot on his copybook" [syn: blot, smear,
       smirch, spot, stain]
    v 1: smear so as to make dirty or stained [syn: smirch,
         besmirch]
    2: charge falsely or with malicious intent; attack the good name
       and reputation of someone; "The journalists have defamed me!"
       "The article in the paper sullied my reputation" [syn:
       defame, slander, smirch, asperse, denigrate,
       calumniate, smear, sully, besmirch]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "smirch":
   aspersion, attaint, badge of infamy, bar sinister, baton, bedarken,
   bedaub, begrime, bend sinister, besmear, besmirch, besmoke,
   besmutch, besoil, bespatter, bestain, black, black eye, black mark,
   blacken, blackening, blackwash, bloodstain, blot, blotch, blur,
   brand, broad arrow, call names, censure, champain, charcoal, cork,
   dab, darken, darkening, daub, defile, denigrate, denigration,
   dinge, dirty, discolor, disparagement, ebonize,
   engage in personalities, eyesore, fleck, flick, flyspeck, foul,
   grime, heap dirt upon, imputation, ink, macula, maculation, macule,
   mark, mark of Cain, melanization, melanize, muckrake, murk,
   nigrification, nigrify, onus, oversmoke, patch, pillorying,
   point champain, reflection, reprimand, reproach, revile, scorch,
   sear, shade, shading, shadow, singe, slubber, slur, smear,
   smirching, smoke, smooch, smouch, smudge, smudging, smut, smutch,
   smutching, soil, soilage, soilure, soot, spatter, speck, speckle,
   splash, splatter, splotch, spot, stain, stigma, stigmatism,
   stigmatization, stigmatize, sully, taint, tarnish, throw mud at,
   vilify