The Collaborative International Dictionary of English v.0.48:

Blemish \Blem"ish\, n.; pl. Blemishes.
   Any mark of deformity or injury, whether physical or moral;
   anything that diminishes beauty, or renders imperfect that
   which is otherwise well formed; that which impairs
   reputation.
   [1913 Webster]

         He shall take two he lambs without blemish, and one ewe
         lamb of the first year without blemish.  --Lev. xiv.
                                                  10.
   [1913 Webster]

         The reliefs of an envious man are those little
         blemishes and imperfections that discover themselves in
         an illustrious character.                --Spectator.
   [1913 Webster]

   Syn: Spot; speck; flaw; deformity; stain; defect; fault;
        taint; reproach; dishonor; imputation; disgrace.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Blemish \Blem"ish\, v. t. [imp. & p. p. Blemished; p. pr. &
   vb. n. Blemishing.] [OE. blemissen, blemishen, OF. blemir,
   blesmir, to strike, injure, soil, F. bl[^e]mir to grow pale,
   fr. OF. bleme, blesme, pale, wan, F. bl[^e]me, prob. fr. Icel
   bl[=a]man the livid color of a wound, fr. bl[=a]r blue; akin
   to E. blue. OF. blemir properly signifies to beat one (black
   and) blue, and to render blue or dirty. See Blue.]
   1. To mark with deformity; to injure or impair, as anything
      which is well formed, or excellent; to mar, or make
      defective, either the body or mind.
      [1913 Webster]

            Sin is a soil which blemisheth the beauty of thy
            soul.                                 --Brathwait.
      [1913 Webster]

   2. To tarnish, as reputation or character; to defame.
      [1913 Webster]

            There had nothing passed between us that might
            blemish reputation.                   --Oldys.
      [1913 Webster]

WordNet (r) 3.0 (2006):

blemish
    n 1: a mark or flaw that spoils the appearance of something
         (especially on a person's body); "a facial blemish" [syn:
         blemish, defect, mar]
    v 1: mar or spoil the appearance of; "scars defaced her cheeks";
         "The vandals disfigured the statue" [syn: deface,
         disfigure, blemish]
    2: mar or impair with a flaw; "her face was blemished" [syn:
       blemish, spot]
    3: add a flaw or blemish to; make imperfect or defective [syn:
       flaw, blemish]

Moby Thesaurus II by Grady Ward, 1.0:

251 Moby Thesaurus words for "blemish":
   abrade, abrasion, baboon, bag, bark, besmirch, birthmark,
   black sheep, blaze, blaze a trail, blister, bloody, blot, blotch,
   brand, break, bruise, bug, burn, caste mark, catch, chafe, chalk,
   chalk up, check, check off, checkmark, chip, cicatrix, cicatrize,
   claw, concussion, crack, crackle, craze, cut, damage, dapple, dash,
   deface, defect, defection, deficiency, define, deform, delimit,
   demarcate, discolor, discoloration, disfigure, disfigurement,
   disproportion, distort, dog, dot, drawback, dysphemize, earmark,
   engrave, engraving, erratum, error, eyesore, failing, failure,
   fault, faute, flash burn, flaw, fleck, flick, foible, foreign body,
   foreign intruder, fracture, frailty, fray, frazzle, freckle, fret,
   fright, gall, gargoyle, gash, graving, hack, hag, harm, harridan,
   hatch, hole, hurt, impair, impairment, imperfection, impress,
   imprint, impurity, inadequacy, incise, incision, infirmity, injure,
   injury, intruder, jot, kink, lacerate, laceration, lentigo, lesion,
   line, little problem, look a fright, look a mess, look bad,
   look like hell, look something terrible, macula, maim, make a mark,
   make mincemeat of, mar, mark, mark off, mark out, marking, maul,
   mess, misfit, misshape, mole, monkey wrench, monster, monstrosity,
   mortal wound, mote, mottle, mutilate, mutilation, nevus, nick,
   no beauty, notch, oddball, offend, offend the eye, patch, pencil,
   pepper, pierce, pockmark, point, polka dot, prejudice, prick,
   print, problem, punch, punctuate, puncture, rend, rent, riddle,
   rift, rip, run, rupture, savage, scab, scald, scar, scarecrow,
   scarification, scarify, scorch, score, scotch, scrape, scratch,
   scratching, scuff, seal, seam, second-degree burn, shortcoming,
   sight, skin, slash, slit, sliver, smear, snag, something missing,
   sore, speck, speckle, splash, splinter, split, splotch, spoil,
   spot, sprain, stab, stab wound, stain, stamp, stick, stigma,
   stigmatize, stone, strain, strawberry mark, streak, striate,
   stripe, sully, taint, tarnish, tattoo, tattoo mark, tear, teratism,
   third-degree burn, tick, tick off, tittle, trace, trauma,
   traumatize, truncate, twist, uglify, ugly duckling, underline,
   underscore, vice, vitiate, vulnerable place, warp, wart, watermark,
   weak link, weak point, weakness, weed, witch, wound,
   wounds immedicable, wrench



Easton's 1897 Bible Dictionary:

Blemish
   imperfection or bodily deformity excluding men from the
   priesthood, and rendering animals unfit to be offered in
   sacrifice (Lev. 21:17-23; 22:19-25). The Christian church, as
   justified in Christ, is "without blemish" (Eph. 5:27). Christ
   offered himself a sacrifice "without blemish," acceptable to God
   (1 Pet. 1:19).