Definition of ex post facto in English:

ex post facto

adjective & adverb

  • With retrospective action or force:

    [as adjective] ‘ex post facto laws’
    backdated, retroactive, ex post facto, backward-looking
    View synonyms

Origin

Erroneous division of Latin ex postfacto in the light of subsequent events.

Pronunciation:

ex post facto

/ˌɛks pəʊst ˈfaktəʊ/