ret‧ro‧ac‧tive /ˌretrəʊˈæktɪv◂ $ -troʊ-/
adjective formal a law or decision that is retroactive is effective from a particular date in the past
Synonym : retrospective:
a retroactive pay increaseretroactive to
The legislation is retroactive to 1st June.—retroactively adverb [TahlilGaran] Dictionary of Contemporary English ▲