Source : Webster's Revised Unabridged Dictionary (1913)

Unacceptable \Un`ac*cept"a*ble\, a.
   Not acceptable; not pleasing; not welcome; unpleasant;
   disagreeable; displeasing; offensive. --
   {Un`ac*cept"a*ble*ness}, n. -- {Un`ac*cept"a*bly}, adv.

Source : WordNet®

unacceptableness
     n : unsatisfactoriness by virtue of not conforming to approved
         standards [syn: {unacceptability}] [ant: {acceptability}]