retroactive

Influencing or applying to a period prior to enactment.

Retroacting; having a reversed or retrospective action; operative with respect to past circumstances; holding good for preceding cases.

Fitted or designed to retroact; operating by returned action; affecting what is past; retrospective.

one which operates to make criminal or punishable, or in any way expressly to affect, acts done prior to the passing of the law.

Extending in scope, effect, application or influence to a prior time or to prior conditions

descriptive of any event or stimulus or process that has an effect on the effects of events or stimuli or process that occurred previously

affecting things past