The Collaborative International Dictionary of English v.0.48:

Blur \Blur\ (bl[^u]r), v. t. [imp. & p. p. Blurred (bl[^u]rd);
   p. pr. & vb. n. Blurring.] [Prob. of same origin as blear.
   See Blear.]
   1. To render obscure by making the form or outline of
      confused and uncertain, as by soiling; to smear; to make
      indistinct and confused; as, to blur manuscript by
      handling it while damp; to blur the impression of a
      woodcut by an excess of ink.
      [1913 Webster]

            But time hath nothing blurred those lines of favor
            Which then he wore.                   --Shak.
      [1913 Webster]

   2. To cause imperfection of vision in; to dim; to darken.
      [1913 Webster]

            Her eyes are blurred with the lightning's glare.
                                                  --J. R. Drake.
      [1913 Webster]

   3. To sully; to stain; to blemish, as reputation.
      [1913 Webster]

            Sarcasms may eclipse thine own,
            But can not blur my lost renown.      --Hudibras.
      [1913 Webster]

   Syn: To spot; blot; disfigure; stain; sully.
        [1913 Webster]