retroactively
retroactively — adverb
1. applying to a time in the past, so that a new law, rule, or payment also covers
applying to a time in the past, so that a new law, rule, or payment also covers things that happened before it was made
The new safety rule was applied retroactively to buildings finished last year.
passive: be applied retroactively to [things]
Kofi's company raised wages retroactively, paying staff extra for the past three months.
retroactively with pay, covering a past period
The school changed its grading policy retroactively, affecting every test taken since September.
Esme feared the higher fee would apply retroactively to months she had already paid.
The court ruled that the ban could not take effect retroactively against past contracts.
- retrospectively
often interchangeable, but leans toward reviewing the past rather than legally back-dating an effect
- ex post facto
formal legal Latin; used specifically of laws that reach back to acts done before they existed
- prospectively
applying only from now forward, never to the past
用法筆記
Often passive (be applied/charged retroactively) and typically pairs with laws, taxes, pay rises, or official rulings rather than everyday actions.