[syn: brainsick, crazy, demented, disturbed, mad, sick, unbalanced, unhinged]
3.  debits and credits are not equal; 
The Collaborative International Dictionary of English v.0.48:
Unbalanced \Un*bal"anced\, a. [In senses 1 and 2, pref. un- not
   + balanced; in sense 3, 1st pref. un- + balance.]
   1. Not balanced; not in equipoise; having no counterpoise, or
      having insufficient counterpoise.
      [1913 Webster]
            Let Earth unbalanced from her orbit fly. --Pope.
      [1913 Webster]
   2. (Com.) Not adjusted; not settled; not brought to an
      equality of debt and credit; as, an unbalanced account;
      unbalanced books.
      [1913 Webster]
   3. Being, or being thrown, out of equilibrium; hence,
      disordered or deranged in sense; unsteady; unsound; as, an
      unbalanced mind. --Pope.
      [1913 Webster]
WordNet (r) 3.0 (2006):
unbalanced
    adj 1: being or thrown out of equilibrium [syn: unbalanced,
           imbalanced] [ant: balanced]
    2: affected with madness or insanity; "a man who had gone mad"
       [syn: brainsick, crazy, demented, disturbed, mad,
       sick, unbalanced, unhinged]
    3: debits and credits are not equal
Moby Thesaurus II by Grady Ward, 1.0:
96 Moby Thesaurus words for "unbalanced":
   abnormal, asymmetric, asymmetrical, batty, bereft of reason,
   bonkers, brainsick, canted, certifiable, crackbrained, cracked,
   crazed, crazy, daffy, daft, deluded, demented, deprived of reason,
   deranged, disoriented, disproportionate, distraught, disturbed,
   dizzy, eccentric, flighty, hallucinated, heeling, ill-balanced,
   illegal, inequitable, iniquitous, insane, irrational, irregular,
   leaning, listing, loco, lopsided, lunatic, mad, maddened, manic,
   mazed, mental, mentally deficient, meshuggah, moon-struck,
   non compos, non compos mentis, nonsymmetrical, not all there,
   not right, nuts, odd, of unsound mind, off, off-balance,
   off-center, overbalanced, psycho, queer, reasonless, senseless,
   shaky, sick, stark-mad, stark-staring mad, strange, tetched,
   top-heavy, touched, uncentered, undeserved, undue, unequal,
   unequitable, uneven, unhinged, unjust, unlawful, unmeet, unmerited,
   unrightful, unsane, unsettled, unsound, unstable, unsteady,
   unsymmetrical, wacky, wandering, witless, wobbly, wrong,
   wrongful