The Collaborative International Dictionary of English v.0.48:

Disproportion \Dis`pro*por"tion\, n. [Pref. dis- + proportion:
   cf. F. disproportion.]
   1. Want of proportion in form or quantity; lack of symmetry;
      as, the arm may be in disproportion to the body; the
      disproportion of the length of a building to its height.
      [1913 Webster]

   2. Want of suitableness, adequacy, or due proportion to an
      end or use; unsuitableness; disparity; as, the
      disproportion of strength or means to an object.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Disproportion \Dis`pro*por"tion\, v. t. [imp. & p. p.
   Disproportioned; p. pr. & vb. n. Disproportioning.]
   To make unsuitable in quantity, form, or fitness to an end;
   to violate symmetry in; to mismatch; to join unfitly.
   [1913 Webster]

         To shape my legs of an unequal size;
         To disproportion me in every part.       --Shak.
   [1913 Webster]

         A degree of strength altogether disproportioned to the
         extent of its territory.                 --Prescott.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disproportion
    n 1: lack of proportion; imbalance among the parts of something
         [ant: proportion, symmetry]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "disproportion":
   ambiguity, ambivalence, anamorphism, anamorphosis, antinomy,
   asymmetry, buckle, contortion, contrariety, crookedness,
   derangement, detorsion, deviation, difference, disarrangement,
   disarray, disarticulation, discomfiture, discomposure,
   disconcertedness, disequilibrium, disharmony, dishevelment,
   disintegration, disjunction, disorder, disorderliness,
   disorganization, disparity, disproportionateness, disruption,
   dissimilarity, distortion, disturbance, entropy, equivocality,
   gnarl, haphazardness, heresy, heterodoxy, heterogeneity, imbalance,
   imparity, inadequacy, incoherence, incommensurability,
   incompatibility, incongruity, inconsistency, inconsonance,
   indiscriminateness, inequality, inequity, inharmonious harmony,
   injustice, insufficiency, irreconcilability, irregularity, knot,
   lopsidedness, most admired disorder, nonconformability,
   nonconformity, nonsymmetry, nonuniformity, odds, overbalance,
   oxymoron, paradox, perturbation, promiscuity, promiscuousness,
   quirk, randomness, screw, self-contradiction, shortcoming, torsion,
   tortuosity, turbulence, turn, twist, unbalance, unconformability,
   unconformity, unevenness, unfair discrimination, unorthodoxy,
   unsymmetry, ununiformity, upset, warp, wrench, wrest, wring