The Collaborative International Dictionary of English v.0.48:

Acceptilation \Ac*cep`ti*la"tion\, n. [L. acceptilatio entry of
   a debt collected, acquittance, fr. p. p. of accipere (cf.
   Accept) + latio a carrying, fr. latus, p. p. of ferre to
   carry: cf. F. acceptilation.] (Civil Law)
   Gratuitous discharge; a release from debt or obligation
   without payment; free remission.
   [1913 Webster]

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

ACCEPTILATION, contracts. In the civil law, is a release made by a creditor
to his debtor of his debt, without receiving any consideration. Ayl. Pand.
tit. 26, p. 570. It is a species of donation, but not subject to the forms
of the latter, and is valid, unless in fraud of creditors. Merlin, Repert.
de Jurisp. h.t. Acceptilation may be defined verborum conceptio qua
creditor debitori, quod debet, acceptum fert; or, a certain arrangement of
words by which on the question of the debtor, the creditor, wishing to
dissolve the obligation, answers that he admits as received, what in fact,
he has not received. The acceptilation is an imaginary payment. Dig. 46, 4,
1 and 19; Dig. 2, 14, 27, 9; Inst. 3, 30, 1.