The Collaborative International Dictionary of English v.0.48:

Unskillful \Un*skill"ful\, a. [Spelt also unskilful.]
   [1913 Webster]
   1. Not skillful; inexperienced; awkward; bungling; as, an
      unskillful surgeon or mechanic; an unskillful logician.
      [1913 Webster]

   2. Lacking discernment; injudicious; ignorant.
      [1913 Webster]

            Though it make the unskillful laugh, can not but
            make the judicious grieve.            --Shak.
      [1913 Webster] -- Un*skill"ful*ly, adv. --
      Un*skill"ful*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

unskillful
    adj 1: poorly done; "a botchy piece of work"; "it was an
           unskillful attempt" [syn: botchy, butcherly,
           unskillful]

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "unskillful":
   alert, artless, bad, base, black, criminal, deficient, evil,
   half-assed, ill, imperfect, improper, inaccurate, inadept,
   inadequate, inapt, inattentive, inauspicious, incapable,
   incompetent, inefficient, inept, inexpedient, inexpert, inferior,
   insufficient, invalid, little, maladroit, malevolent, mean,
   mediocre, not comparable, not in it, open-eyed, out of it, peccant,
   pedestrian, petty, poor, shabby, sinful, sinister, skill-less,
   small, thoughtless, trivial, unapt, undeft, undexterous,
   undextrous, unfacile, unfavorable, unfitted, unhandy, unhealthy,
   unintelligent, unkind, unpleasant, unproficient, unqualified,
   unready, unskilled, unsleeping, untoward, unworkmanlike, vicious,
   vigilant, wakeful, wicked, wide-awake, wrong