The Collaborative International Dictionary of English v.0.48:

Exoneration \Ex*on`er*a"tion\, n. [L. exoneratio: cf. F.
   Exon['e]ration.]
   The act of disburdening, discharging, or freeing morally from
   a charge or imputation; also, the state of being disburdened
   or freed from a charge.
   [1913 Webster]

WordNet (r) 3.0 (2006):

exoneration
    n 1: the condition of being relieved from blame or obligation
    2: the act of vindicating or defending against criticism or
       censure etc.; "friends provided a vindication of his
       position" [syn: vindication, exoneration]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "exoneration":
   absolution, acquittal, acquittance, amnesty, clearance, clearing,
   compurgation, destigmatization, destigmatizing, discharge,
   disculpation, dismissal, exculpation, excuse, exemption,
   forgiveness, grace, immunity, indemnity, pardon, purgation,
   purging, quietus, quittance, redemption, release, remission,
   remission of sin, reprieve, shrift, sparing, verdict of acquittal,
   vindication



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

EXONERATION. The taking off a burden or duty.
     2. It is a rule in the distribution of an intestate's estate that the
debts which he himself contracted, and for which be mortgaged his land as
security, shall be paid out of the personal estate in exoneration of the
real.
     3. But when the real estate is charged with the payment of a mortgage
at the time the intestate buys it, and the purchase is made subject to it,
the personal. is not in that case to be applied, in exoneration of the real
estate. 2 Pow. Mortg. 780; 5 Hayw. 57; 3 Johns. Ch. R. 229.
     4. But the rule for exonerating the real estate out of the personal,
does not apply against specific or pecuniary legatees, nor the widow's right
to paraphernalia, and with reason not against the interest of creditors. 2
Ves. jr. 64; 1 P. Wms. 693; Id. 729; 2 Id. 120,335; 3 Id. 367. Vide Pow.
Mortg. Index, h.t.