Retroactive
Pronunciation : Re`tro*act"ive
Part of Speech : a.
Etymology : [Cf. F. r?troactif.]
Definition : Defn: Fitted or designed to retroact; operating by returned action; affecting what is past; retrospective. Beddoes. Retroactive law or statute (Law), one which operates to make criminal or punishable, or in any way expressly to affect, acts done prior to the passing of the law.
Source : Webster's Unabridged Dictionary, 1913