ad. Done after the fact; applying to events that have previously transpired.
the GNU version of the Collaborative International Dictionary of English
ad. In a retroactive manner.
The Century Dictionary and Cyclopedia
In a retroactive manner; with reversed or retrospective action.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
ad. after the fact
Word Usage
"I'm not a lawyer, but I think the concept of applying a law retroactively is contrary both to the letter and the spirit of our laws and Constitution."