The Collaborative International Dictionary of English v.0.48:

Accountability \Ac*count`a*bil"i*ty\, n.
   The state of being accountable; liability to be called on to
   render an account; the obligation to bear the consequences
   for failure to perform as expected; accountableness. "The
   awful idea of accountability." --R. Hall.

   Syn: answerability, answerableness
        [1913 Webster]

WordNet (r) 3.0 (2006):

accountability
    n 1: responsibility to someone or for some activity [syn:
         accountability, answerability, answerableness]

The Devil's Dictionary (1881-1906):

ACCOUNTABILITY, n.  The mother of caution.

    "My accountability, bear in mind,"
        Said the Grand Vizier:  "Yes, yes,"
    Said the Shah:  "I do -- 'tis the only kind
        Of ability you possess."
                                                            Joram Tate