The Collaborative International Dictionary of English v.0.48:

Uneven \Un*e"ven\, a. [AS. unefen. See Un- not, and Even,
   a.]
   1. Not even; not level; not uniform; rough; as, an uneven
      road or way; uneven ground.
      [1913 Webster]

   2. Not equal; not of equal length.
      [1913 Webster]

            Hebrew verse consists of uneven feet. --Peacham.
      [1913 Webster]

   3. Not divisible by two without a remainder; odd; -- said of
      numbers; as, 3, 7, and 11 are uneven numbers.
      [1913 Webster] Un*e"ven*ly, adv. -- Un*e"ven*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

unevenness
    n 1: the quality of being uneven and lacking uniformity [syn:
         unevenness, variability] [ant: evenness,
         invariability]
    2: the quality of being unbalanced [ant: evenness]