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.
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         The reliefs of an envious man are those little
         blemishes and imperfections that discover themselves in
         an illustrious character.                --Spectator.
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   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.
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   2. To tarnish, as reputation or character; to defame.
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            There had nothing passed between us that might
            blemish reputation.                   --Oldys.
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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]