The Collaborative International Dictionary of English v.0.48:

Unman \Un*man"\, v. t. [1st pref. un- + man.]
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   1. To deprive of the distinctive qualities of a human being,
      as reason, or the like. [R.] --South.
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   2. To emasculate; to deprive of virility.
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   3. To deprive of the courage and fortitude of a man; to break
      or subdue the manly spirit in; to cause to despond; to
      dishearten; to make womanish.
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            Let's not unman each other.           --Byron.
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   4. To deprive of men; as, to unman a ship.
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