The Collaborative International Dictionary of English v.0.48:

Guilt \Guilt\ (g[i^]lt), n. [OE. gilt, gult, AS. gylt, crime;
   probably originally signifying, the fine or mulct paid for an
   offence, and afterward the offense itself, and akin to AS.
   gieldan to pay, E. yield. See Yield, v. t.]
   1. The criminality and consequent exposure to punishment
      resulting from willful disobedience of law, or from
      morally wrong action; the state of one who has broken a
      moral or political law; crime; criminality; offense
      against right.
      [1913 Webster]

            Satan had not answer, but stood struck
            With guilt of his own sin.            --Milton.
      [1913 Webster]

   2. Exposure to any legal penalty or forfeiture.
      [1913 Webster]

            A ship incurs guilt by the violation of a blockade.
                                                  --Kent.
      [1913 Webster]

   3. A feeling of regret or remorse for having committed some
      improper act; a recognition of one's own responsibility
      for doing something wrong. "Depression is often rooted in
      guilt which has not been dealt with in an appropriate
      way." "Guilt is a natural and appropriate consequence to a
      wrong action."
      [PJC]

WordNet (r) 3.0 (2006):

guilt
    n 1: the state of having committed an offense [syn: guilt,
         guiltiness] [ant: innocence]
    2: remorse caused by feeling responsible for some offense [syn:
       guilt, guilty conscience, guilt feelings, guilt trip]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "guilt":
   blame, blameworthiness, contriteness, contrition, crime,
   criminality, culpability, fault, feloniousness, guiltiness,
   misconduct, offense, onus, regret, remorse, repentance,
   responsibility, self-condemnation, self-reproach, shame, sin,
   sinfulness, sorrow, wrongdoing



Bouvier's Law Dictionary, Revised 6th Ed (1856):

GUILT, crim. law. That quality which renders criminal and liable to
punishment; or it is that disposition to violate the law, which has
manifested itself by some act already done. The opposite of innocence. Vide
Rutherf. Inst. B. 1, c. 18, s. 10.
     2. In general everyone is presumed innocent until guilt has been
proved; but in some cases the presumption of guilt overthrows that of
innocence; as, for example, where a party destroys evidence to which the
opposite party is entitled. The spoliation of papers, material to show the
neutral character of a vessel, furnishes strong presumption against the
neutrality of the ship. 2 Wheat. 227. Vide Spoliation.