The Collaborative International Dictionary of English v.0.48:

Clumsy \Clum"sy\, a. [Compar. Clumsier; superl. Clumsiest.]
   [OE. clumsed benumbed, fr. clumsen to be benumbed; cf. Icel.
   klumsa lockjaw, dial. Sw. klummsen benumbed with cold. Cf.
   1st Clam, and 1st Clamp.]
   1. Stiff or benumbed, as with cold. [Obs.]
      [1913 Webster]

   2. Without skill or grace; wanting dexterity, nimbleness, or
      readiness; stiff; awkward, as if benumbed; unwieldy;
      unhandy; hence; ill-made, misshapen, or inappropriate; as,
      a clumsy person; a clumsy workman; clumsy fingers; a
      clumsy gesture; a clumsy excuse.
      [1913 Webster]

            But thou in clumsy verse, unlicked, unpointed,
            Hast shamefully defied the Lord's anointed.
                                                  --Dryden.

   Syn: See Awkward.
        [1913 Webster]

WordNet (r) 3.0 (2006):

clumsy
    adj 1: lacking grace in movement or posture; "a gawky lad with
           long ungainly legs"; "clumsy fingers"; "what an ungainly
           creature a giraffe is"; "heaved his unwieldy figure out
           of his chair" [syn: gawky, clumsy, clunky,
           ungainly, unwieldy]
    2: not elegant or graceful in expression; "an awkward prose
       style"; "a clumsy apology"; "his cumbersome writing style";
       "if the rumor is true, can anything be more inept than to
       repeat it now?" [syn: awkward, clumsy, cumbersome,
       inapt, inept, ill-chosen]
    3: difficult to handle or manage especially because of shape;
       "an awkward bundle to carry"; "a load of bunglesome
       paraphernalia"; "clumsy wooden shoes"; "the cello, a rather
       ungainly instrument for a girl" [syn: awkward,
       bunglesome, clumsy, ungainly]
    4: showing lack of skill or aptitude; "a bungling workman"; "did
       a clumsy job"; "his fumbling attempt to put up a shelf" [syn:
       bungling, clumsy, fumbling, incompetent]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "clumsy":
   Doric, all thumbs, awkward, barbaric, barbarous, blunderheaded,
   blundering, boorish, botched, bovine, bulky, bumbling, bungling,
   butterfingered, cacophonous, careless, cloddish, clownish,
   clumsy-fisted, coarse, contrary, crosswise, crude, cumbersome,
   cumbrous, deficient, discommodious, doggerel, dysphemistic,
   elephantine, fingers all thumbs, fumbling, gauche, gawkish, gawky,
   graceless, gross, half-assed, ham-fisted, ham-handed, haphazard,
   harsh, heavy-handed, hit-and-miss, hit-or-miss, hulking, hulky,
   impractical, improper, impure, in bad taste, incommodious,
   inconcinnate, inconcinnous, inconvenient, incorrect, indecorous,
   inelegant, inept, infelicitous, left-hand, left-handed, loutish,
   low, lubberly, lumbering, lumpish, lumpy, maladroit, massive,
   massy, messy, oafish, outlandish, perverse, ponderous, promiscuous,
   rude, slipshod, slipshoddy, sloppy, slovenly, sluttish, splay,
   stiff, tasteless, troublesome, uncourtly, uncouth, undignified,
   uneuphonious, unfelicitous, ungainly, ungraced, ungraceful,
   unhandy, unhappy, unmanageable, unpolished, unrefined, unseemly,
   untidy, unwieldy, vulgar, wooden