The Collaborative International Dictionary of English v.0.48:

Penitence \Pen"i*tence\, n. [F. p['e]nitence, L. paenitentia.
   See Penitent, and cf. Penance.]
   The quality or condition of being penitent; the disposition
   of a penitent; sorrow for sins or faults; repentance;
   contrition. "Penitence of his old guilt." --Chaucer.
   [1913 Webster]

         Death is deferred, and penitenance has room
         To mitigate, if not reverse, the doom.   --Dryden.
   [1913 Webster]

   Syn: Repentance; contrition; compunction.
        [1913 Webster]

WordNet (r) 3.0 (2006):

penitence
    n 1: remorse for your past conduct [syn: repentance,
         penitence, penance]