Wordnet 3.0
ADVERB (2)
1. 
 out of proportion; 
- Example: "this wall is disproportionately long"2. 
 to a disproportionate degree; 
- Example: "his benefits were disproportionately generous"
The Collaborative International Dictionary of English v.0.48:
Disproportionate \Dis`pro*por"tion*ate\, a.
   Not proportioned; unsymmetrical; unsuitable to something else
   in bulk, form, value, or extent; out of proportion;
   inadequate; as, in a perfect body none of the limbs are
   disproportionate; it is wisdom not to undertake a work
   disproportionate means. -- Dis`pro*por"tion*ate*ly, adv. --
   Dis`pro*por"tion*ate*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
disproportionately
    adv 1: out of proportion; "this wall is disproportionately long"
           [ant: proportionately]
    2: to a disproportionate degree; "his benefits were
       disproportionately generous" [ant: proportionally,
       proportionately]