adjective (a)

• poorly balanced or matched in quantity or value or measure(adj.all)

  Antonym:
  equal
  

  source: wordnet30
• lacking the requisite qualities or resources to meet a task(adj.all)

  Example:
  She was unequal to the task.
  

  Synonym:
  inadequate
  Antonym:
  adequate, equal
  

  source: wordnet30
• 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.(adjective)

  source: webster1913