The Collaborative International Dictionary of English v.0.48:

Lopsided \Lop"sid`ed\, a. [Lop + side. Cf. Lobsided.]
   1. Leaning to one side because of some defect of structure;
      as, a lopsided ship. --Marryat.
      [1913 Webster]

   2. Unbalanced; poorly proportioned; having much more on one
      side than the other; -- also used metaphorically; as, a
      lopsided victory.
      [1913 Webster +PJC]

   3. Full of idiosyncrasies. --J. S. Mill.
      [1913 Webster]

WordNet (r) 3.0 (2006):

lopsided
    adj 1: having one side lower or smaller or lighter than the
           other
    2: turned or twisted toward one side; "a...youth with a gorgeous
       red necktie all awry"- G.K.Chesterton; "his wig was, as the
       British say, skew-whiff" [syn: askew, awry(p),
       cockeyed, lopsided, wonky, skew-whiff]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "lopsided":
   anamorphous, askew, asymmetric, asymmetrical, awry, bent, biased,
   bowed, canted, cockeyed, contorted, crazy, crooked, crumpled,
   crunched, deviative, disproportional, disproportionate, distorted,
   heeling, ill-balanced, irregular, labyrinthine, leaning, listing,
   nonsymmetric, nonsymmetrical, off-balance, one-sided, overbalanced,
   sprung, top-heavy, tortuous, twisted, unbalanced, unequal, uneven,
   unfair, unstable, unsteady, unsymmetric, unsymmetrical, warped