The Collaborative International Dictionary of English v.0.48:

Clutter \Clut"ter\, n. [Cf. W. cludair heap, pile, cludeirio to
   heap.]
   1. A confused collection; hence, confusion; disorder; as, the
      room is in a clutter.
      [1913 Webster]

            He saw what a clutter there was with huge, overgrown
            pots, pans, and spits.                --L'Estrange.
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   2. Clatter; confused noise. --Swift.
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The Collaborative International Dictionary of English v.0.48:

Clutter \Clut"ter\, v. t. [imp. & p. p. Cluttered; p. pr. &
   vb. n. Cluttering.]
   To crowd together in disorder; to fill or cover with things
   in disorder; to throw into disorder; to disarrange; as, to
   clutter a room.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clutter \Clut"ter\, v. i.
   To make a confused noise; to bustle.
   [1913 Webster]

         It [the goose] cluttered here, it chuckled there.
                                                  --Tennyson.
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The Collaborative International Dictionary of English v.0.48:

Clutter \Clut"ter\, v. t. [From Clod, n.]
   To clot or coagulate, as blood. [Obs.] --Holland.
   [1913 Webster]

WordNet (r) 3.0 (2006):

clutter
    n 1: a confused multitude of things [syn: clutter, jumble,
         muddle, fuddle, mare's nest, welter, smother]
    2: unwanted echoes that interfere with the observation of
       signals on a radar screen
    v 1: fill a space in a disorderly way [syn: clutter, clutter
         up] [ant: clear, unclutter]