The Collaborative International Dictionary of English v.0.48:

Unballasted \Un*bal"last*ed\, a.
   1. [Properly p. p. of unballast.] Freed from ballast; having
      discharged ballast.
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   2. [Pref. un- not + ballasted.] Not furnished with ballast;
      not kept steady by ballast; unsteady; as, unballasted
      vessels; unballasted wits.
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            Unballasted by any sufficient weight of plan. --De
                                                  Quincey.
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