ex post facto

adverb | \ ˈeks-ˌpōst-ˈfak-tō \
  1. : after the fact : retroactively cannot judge ex post facto

ex post facto

adjective
  1. : done, made, or formulated after the fact : retroactive

  1. : of or relating to an ex post facto law the chief concerns of the ex post facto ban —L. H. Tribe