Source : Webster's Revised Unabridged Dictionary (1913)

Mar \Mar\, v. t. [imp. & p. p. {Marred} (m["a]rd); p. pr. & vb.
   n. {Marring}.] [OE. marren, merren, AS. merran, myrran (in
   comp.), to obstruct, impede, dissipate; akin to OS. merrian,
   OHG. marrjan, merran; cf. D. marren, meeren, to moor a ship,
   Icel. merja to bruise, crush, and Goth. marzjan to offend.
   Cf. {Moor}, v.]
   1. To make defective; to do injury to, esp. by cutting off or
      defacing a part; to impair; to disfigure; to deface.

            I pray you mar no more trees with wiring love songs
            in their barks.                       --Shak.

            But mirth is marred, and the good cheer is lost.
                                                  --Dryden.

            Ire, envy, and despair Which marred all his borrowed
            visage.                               --Milton.

   2. To spoil; to ruin. ``It makes us, or it mars us.''
      ``Striving to mend, to mar the subject.'' --Shak.

Source : WordNet®

marred
     adj 1: having the surface damaged or disfigured [syn: {defaced}]
     2: blemished by injury or rough wear; "the scarred piano
        bench"; "walls marred by graffiti" [syn: {scarred}]

mar
     v 1: make imperfect; "nothing marred her beauty" [syn: {impair},
          {spoil}, {deflower}, {vitiate}]
     2: destroy or injure severely; "mutilated bodies" [syn: {mutilate}]
     [also: {marring}, {marred}]

marred
     See {mar}