The Collaborative International Dictionary of English v.0.48:

Condonation \Con`do*na"tion\, n. [L. condonatio a giving away.]
   1. The act of condoning or pardoning.
      [1913 Webster]

   2. (Law) Forgiveness, either express or implied, by a husband
      of his wife or by a wife of her husband, for a breach of
      marital duty, as adultery, with an implied condition that
      the offense shall not be repeated. --Bouvier. Wharton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

condonation
    n 1: a pardon by treating the offender as if the offense had not
         occurred

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

CONDONATION. A term used in the canon law. It is a forgiveness by the
husband of his wife, or by a wife of her husband, of adultery committed,
with an implied condition that the injury shall not be repeated, and that
the other party shall be treated with conjugal kindness. 1 Hagg. R. 773; 3
Eccl. Rep. 310. See 5 Mass. 320 5 Mass. 69; 1 Johns. Ch. R. 488.
     2. It may be express or implied, as, if a husband, knowing of his
wife's infidelity, cohabit with her. 1 Hagg. Rep. 789; 3 Eccl. R. 338.
     3. Condonation is not, for many rea sons, held so strictly against a
wife as against a husband. 3 Eccl. R. 830 Id. 341, n.; 2 Edw. R. 207. As all
condonations, by operation of law, are expressly or impliedly conditional,
it follows that the effect is taken off by the repetition of misconduct; 3
Eccl. R. 329 3 Phillim. Rep. 6; 1 Eccl. R. 35; and cruelty revives condoned
adultery. Worsley v. Worsley, cited in Durant v. Durant, 1 Hagg. Rep. 733; 3
Eccl. Rep. 311.
     4. In New York, an act of cruelty alone, on the part of the husband,
does not revive condoned adultery, to entitle the wife to a divorce. 4
Paige's R. 460. See 3 Edw. R. 207.
     5. Where the parties have separate beds, there must, in order to found
condonation, be something of matrimonial intercourse presumed; it does not
rest merely on the wife's not. withdrawing herself. 3 Eccl. R. 341, n.; 2
Paige, R. 108.
     6. Condonation is a bar to a sentence of divorce. 1 Eccl. Rep. 284; 2
Paige, R. 108. In Pennsylvania, by the Act of the 13th of March, 1815, Sec.
7, 6 Reed's Laws of Penna. 288, it is enacted that "in any suit or action
for divorce for cause of adultery, if the defendant shall allege and prove
that the plaintiff has admitted the defendant into conjugal society or
embraces, after he or she knew of the criminal fact, or that the plaintiff
(if the husband) allowed of his wife's prostitutions, or received hire, for
them, or exposed his wife to lewd company, whereby she became ensnared to
the crime aforesaid, it shall be a good defence, and perpetual bar against
the same." The same rule may be found, perhaps, in the codes of most
civilized countries. Villanova Y Manes, Materia Criminal Forense, Obs. 11,
c. 20, n. 4. Vide, generally, 2 Edw. 207; Dev. Eq. R. 352 4 Paige, 432; 1
Edw. R. 14; Shelf. on M. & D. 445; 1 John. Ch. R. 488 4 N. Hamp. R. 462; 5
Mass. 320.