The Collaborative International Dictionary of English v.0.48:

Unequal \Un*e"qual\, a. [Cf. Inequal.]
   1. Not equal; not matched; not of the same size, length,
      breadth, quantity, strength, talents, acquirements, age,
      station, or the like; as, the fingers are of unequal
      length; peers and commoners are unequal in rank.
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   2. Ill balanced or matched; disproportioned; hence, not
      equitable; partial; unjust; unfair.
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            Against unequal arms to fight in pain. --Milton.
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            Jerome, a very unequal relator of the opinion of his
            adversaries.                          --John
                                                  Worthington.
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            To punish me for what you make me do
            Seems much unequal.                   --Shak.
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   3. Not uniform; not equable; irregular; uneven; as, unequal
      pulsations; an unequal poem.
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   4. Not adequate or sufficient; inferior; as, the man was
      unequal to the emergency; the timber was unequal to the
      sudden strain.
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   5. (Bot.) Not having the two sides or the parts symmetrical.
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WordNet (r) 3.0 (2006):

unequal
    adj 1: poorly balanced or matched in quantity or value or
           measure [ant: equal]
    2: lacking the requisite qualities or resources to meet a task;
       "inadequate training"; "the staff was inadequate"; "she was
       unequal to the task" [syn: inadequate, unequal] [ant:
       adequate, equal]