Source : Webster's Revised Unabridged Dictionary (1913)

Muff \Muff\ (m[u^]f), n. [Cf. LG. muff, D. mof, G., Dan., & Sw.
   muff, F. moufle mitten, LL. muffula, MHG. mouwe sleeve, D.
   mouw, and E. muffle, v.]
   1. A soft cover of cylindrical form, usually of fur, worn by
      women to shield the hands from cold.

   2. (Mech.) A short hollow cylinder surrounding an object, as
      a pipe.

   3. (Glass Manuf.) A blown cylinder of glass which is
      afterward flattened out to make a sheet.

   4. [Perhaps a different word; cf. Prov. E. maffle to
      slammer.] A stupid fellow; a poor-spirited person.
      [Colloq.] ``A muff of a curate.'' --Thackeray.

   5. [See 4.] (Baseball) A failure to hold a ball when once in
      the hands.

   6. (Zo["o]l.) The whitethroat. [Prov. Eng.]

Muff \Muff\, v. t. [imp. & p. p. {Muffed}; p. pr. & vb. n.
   {Muffing}.]
   To handle awkwardly; to fumble; to fail to hold, as a ball,
   in catching it.

Source : WordNet®

muff
     n 1: a warm tubular covering for the hands
     2: (sports) dropping the ball [syn: {fumble}]
     v 1: fail to catch, as of a ball
     2: make a mess of, destroy or ruin; "I botched the dinner and
        we had to eat out"; "the pianist screwed up the difficult
        passage in the second movement" [syn: {botch}, {bumble}, {fumble},
         {botch up}, {blow}, {flub}, {screw up}, {ball up}, {spoil},
         {muck up}, {bungle}, {fluff}, {bollix}, {bollix up}, {bollocks},
         {bollocks up}, {bobble}, {mishandle}, {louse up}, {foul
        up}, {mess up}, {fuck up}]